Exposure method and apparatus, and method for fabricating device

ABSTRACT

An exposure method and apparatus simultaneously transfer patterns with various pitches with high resolution. On the pupil surface of an illumination system, nine areas are set. The nine areas are a first area including the optical axis, four second areas each smaller than the first area and arranged along a first circumference surrounding the first area, and four third areas each smaller than the first area and arranged along a second circumference surrounding the first circumference and arranged along a second circumference. The distribution of intensity of light over the pupil surface is so set that the intensities of light over the nine areas are approximately equal to one another, and the intensity of light over the other area is smaller than those over the nine areas. This distribution of intensity of light is set using a diffraction optical element or a diaphragm.

This is a Divisional of U.S. application Ser. No. 11/246,642 filed Oct.11, 2005, which is a Continuation of International Application No.PCT/JP2004/004522 filed Mar. 30, 2004. The entire disclosures of theprior applications are hereby incorporated by reference herein in theirentirety.

TECHNICAL FIELD

The present invention relates to an exposure technology used to transfermask-pattern on substrates such as wafers in a lithography process forfabricating various kinds of devices such as semiconductor elements,liquid crystal displays, thin-film magnetic heads and, more particularlyto an exposure technology using an illuminating technology related tothe so-called deformed illumination. Further, the present inventionrelates to a technology for fabricating the device using the exposuretechnology.

BACKGROUND ART

The apparatus for the projection exposure of the batch exposure systemsuch as the step-and-repeat system or the scan exposure system such asthe step-and-scan system have been used to transfer the pattern of thereticle (or photo-mask etc.) as the mask on the wafers (or vitreousplate etc.) as the substrates intended for exposure in the lithographyprocess for fabricating semiconductor elements (or liquid crystaldisplays etc.). In the kind of apparatus for the projection exposure, itis desirable to transfer various kinds of pattern on the wafers witheach high resolution.

The transferred pattern that requires very fine high resolution is theso-called contact hole. The contact hole includes the densely massedcontact hole having a plurality of predetermined shaped aperturearranged with predetermined fine pitch and the isolated contact holebeing substantially comprised of a single aperture. In order to transferthe pattern of the former densely massed contact hole on the wafer withhigh resolution, the so-called deformed illumination system (deformedlight source system), which allows the amount of light of theillumination light to be enlarged in one or more areas (particularlyfour areas) being eccentric for optical axis at the pupil plane of theillumination system, is effective (refer to Japanese Patent ApplicationsLaid-open No. Hei 5-67558 (corresponding with U.S. Pat. No. 6,094,305)and NO. 2001-176766 (corresponding to U.S. Pat. No. 6,563,567)).

On the other hand, in order to transfer the pattern of the laterisolated contact hole on the wafer with high resolution, theillumination system, which allows the amount of light of theillumination light to be enlarged in a relatively small round areacentering optical axis at the pupil plane of the illumination system,that is, the illumination system that allows the σ value, being acoherence factor of the illumination system to be relatively lessened(hereinafter, it will be called “small σ illumination system” forconvenience of description), is known to be effective.

DISCLOSURE OF THE INVENTION

As described above, the pattern of the densely massed contact hole withfine pitch and the isolated contact hole can be transferred on the waferwith high resolution through the deformed illumination system and thesmall σ illumination system respectively. Recently with regard to this,for example, in fabricating semiconductor elements, it is becoming arequirement that transferring one reticle pattern being formed, thepattern being of the contact hole, with various kinds of pitch, whichinclude the patterns ranging from the contact hole arranged with greatpitch, which can be substantially regarded as the isolated contact hole,to the densely massed contact hole with fine pitch, on the wafer at onetime exposure.

For that reason, however, it is a disadvantage that when using thedeformed illumination system, the resolution is not sufficient for thecontact hole with large pitch; while when using the small σ illuminationsystem, the resolution is not sufficient for the densely massed contacthole with fine pitch.

Further, recently, for example, when fabricating semiconductors, it hascome to be demanded to transfer the pattern of the so-called contacthole densely massed in one direction, which is arranged in the onedirection with fine pitch and can be substantially regarded as theisolated pattern in terms of the direction orthogonal to it, to waferwith high resolution.

However, it is a disadvantage that the resolution is not sufficient inthe direction in which the pattern can be regarded as the isolatedpattern, with using the traditional deformed illumination system forthis purpose. Whereas, it is not sufficient in the direction in whichthe pattern is arranged with the fine pitch, with using the small σillumination system.

Considering this problem, the first object of the present invention isto provide an exposure technology for simultaneously transferring thepattern having various kinds of pitches with high resolutionrespectively.

And the second object of the present invention is to provide an exposuretechnology for transferring the pattern, which is arranged in onedirection periodically and is substantially isolated (pattern denselymassed in one direction) in terms of the orthogonal direction, with highresolution.

And the third object of the present invention is to provide amanufacturing technology for fabricating the device including variouskinds of patterns or including the pattern densely massed in onedirection with high accuracy and yet high throughput.

The first exposure method according to the present invention, which isan exposure method for illuminating a mask with an optical beam from anillumination system to expose a substrate with the optical beam throughthe mask and a projection system, characterized in that a light amountdistribution of the optical beam on a predetermined plane with respectto the illumination system is set such that an amount of light is setlarger in nine areas than in an area other than the nine areas, the nineareas including a first area and eight areas, an outer contour of thefirst area including an optical axis of the illumination system, and theeight areas being arranged so as to encompass the first area and each ofthe eight areas being smaller than the first area.

According to the present invention, such a pattern that is great inpitch and can be substantially regarded as the isolated contact hole bymeans of the optical beam passing through the first area is transferredwith high resolution, and the pattern which includes the patternsranging from the pattern with around middle pitch to the pattern withfine pitch like the densely massed contact hole by means of the opticalbeam passing through the eight areas enclosing the first area, istransferred with high resolution. Accordingly, it is, able tosimultaneously transfer the patterns having various kinds of pitcheswith high resolution respectively.

In this case, it is preferable that the first area to be located at thecenter is an annular zone area. With the annular illumination at thefirst area, the resolution and the depth of focus might be improved insome cases. Furthermore, the amount of light (intensity per unit areae.g.) at the first area to be located in the center may be madedifferent from the amount of light at the surround areas enclosing it.

Furthermore, as an example, the predetermined plane is a pupil plane ofthe illumination system, and the nine areas in which the amount of lighton the predetermined plane is greater than the amount of light at thearea other than the nine areas, comprises the first area, four secondareas which are arranged along a first circumference that encloses thefirst area and which are respectively smaller than the first area, andfour third areas which are arranged along a second circumference thatencloses the first circumference and which are respectively smaller thanthe first area.

With this composition, the pattern having the around middle pitch istransferred with high resolution by means of the optical beam passingthrough the second areas, and the pattern having the fine pitch istransferred with high resolution by means of the optical beam passingthrough the third areas.

Furthermore, it is preferable that the first area, two of the secondareas, and two of the third areas are arranged along a first straightline passing through the optical axis of the illumination system, andthe first area, the other two of the second areas, and the other two ofthe third areas are arranged along a second straight line which isorthogonal to the first straight line and which passes through theoptical axis of the illumination system.

The conventional pattern intended to transfer is two-dimensionallyarranged along two directions orthogonal to each other (one of them willbe called “arranging direction of pattern”). Then, by making thedirection of the first straight line (or the second straight line)intersect the arranging direction of the pattern (preferably making itintersect at 45 degree), the pattern having various kinds of the pitchestwo-dimensionally arranged can be transferred with high resolutionrespectively.

Further, the radius (r1) when the first area is made circular, and theradii (r2, r3) when the second and third areas are made circular arepreferably set to the following bounds with the maximum σ value (thiswill be assumed σ) of the illumination system assumed to be a reference.In addition, also if the first area, second areas, and third areas areset to other shape different from the circles such as the square, theregular hexagon or the shape having one quarter circle, the sizes ofthem preferable equal those of the circulars. In addition, if the firstarea is annular, the outer radius (r1) is preferably set to the boundsof an equation (1), as follows:0.2σ≦r1≦0.4σ  (1)0.075σ≦r2≦0.2σ  (2)0.075σ≦r3≦0.2σ  (3)

If each area becomes smaller than the lower limit of the equation (1),equation (2), and equation (3), there is a possibility that theresolution deteriorates for some patterns from among the patterns havingvarious kinds of the pitches. On the other hand, if each area becomesgreater than the upper limit of the equation (1), equation (2), andequation (3), there is a possibility that the resolution deterioratesfor the pattern having fine pitch because this system will be close tothe conventional illumination system.

Next, the second exposure method according to the present invention,which is an exposure method for illuminating a mask with an optical beamfrom an illumination system to expose a substrate with the optical beamthrough the mask and a projection system, has a step of setting a lightamount distribution of the optical beam on a predetermined plane withrespect to the illumination system is set such that an amount of lightis set larger in five areas than in an area other than the five areas,the five areas including a first area of an annular zone shape in whichan outer contour of the first area including an optical axis of theillumination system, and the four areas being arranged so as toencompass the first area and each of the four areas being smaller thanthe first area.

According to the present invention, such a pattern that is large in thepitch and can be substantially regarded as the isolated contact hole istransferred by means of the optical beam passing through the annularfirst area is transferred with high resolution, and the pattern havingfine pitch like the densely massed contact hole by means of the opticalbeam passing through the four areas enclosing the first area istransferred with high resolution. Accordingly, it is able tosimultaneously transfer the patterns having various kinds of the pitcheswith high resolution respectively.

Further, as an example, the predetermined plane is a pupil plane of theillumination system, and the five areas in which the amount of light onthe predetermined plane is greater than the amount of light at the areaother than the five areas, comprises the first area and four secondareas which are arranged, at intervals of substantially 90 degreetherebetween, along a circumference that encloses the first area andwhich are respectively smaller than the first area.

With this composition, the pattern having the fine pitch is transferredwith high resolution by means of the optical beam passing through thesecond areas. The conventional pattern intended to transfer istwo-dimensionally arranged along two directions orthogonal to each other(one of them will be called “arranging direction of pattern”). Then, bymaking the direction, in which the second areas are arranged intersectthe arranging direction of the pattern (preferably making it intersectat 45 degree) the pattern having various kinds of the pitchestwo-dimensionally arranged can be transferred with high resolutionrespectively.

Further, it is preferable that the radius (r1) when the first area ismade annular with its contour assumed to be circular and the radius (r2)when the second area is made circular is preferably set within thebounds of the equations (1) and (2) described above with the maximum σvalue (this will be assumed σ) of the illumination system assumed to bea reference. This enables the pattern having various kinds of thepitches to be transferred with high resolution.

In the present invention, an optical beam generated from each of theareas which have large amount of light which are arranged out of theoptical axis of the illumination system on the predetermined plane islinear polarization. In this case, a direction of polarization of theoptical beam on the predetermined plane is substantially coincident witha circumference direction (that is, the optical beam may be Spolarization).

Next, the third method for exposure according to the present invention,which is an exposure method having a step for illuminating a mask withan optical beam from an illumination system to expose a substrate withthe optical beam through the mask and a projection system, has a step ofsetting a light amount distribution of the optical beam on apredetermined plane with respect to the illumination system is set suchthat an amount of light is set larger in three areas than in the areaother than these.

According to the present invention, if one direction dense patterns areformed at the mask, the patterns are transferred with high resolutionthe direction of which the patterns are isolate by means of optical beampassing through the center of the three areas, and the patterns aretransferred with high resolution the direction of which the patterns areperiodically arranged by means of optical beam passing through the twoareas which sandwich the center area.

In this case, the three areas having large amount of light include afirst area near an optical axis of the illumination system, and a secondarea and a third area which are arranged along a straight line passingthrough the optical axis so as to sandwich the first area.Alternatively, the three areas having large amount of light include afirst area near an optical axis of the illumination system, and a secondarea and a third area which are arranged with the approximately samedistance from the optical axis.

With these compositions, by providing (paralleling) the direction ofwhich the three areas are arranged to the direction of which the onedirection dense pattern is periodically arranged, it is able to transferthe one directional high density pattern to the two directions of theisolated and periodical ones with high resolution.

In other words, if a pattern formed on the mask includes a onedirectionally high density pattern which is periodically arranged alonga predetermined first axis and which is substantially isolated in adirection of a second axis orthogonal to the first axis, the three areashaving large amount of light are preferably arranged with a distancetherebetween in a parallel direction to the first axis. Whereby, it isable to transfer the one directional high density pattern with highresolution along the first axis and the second axis respectively.Further, the three areas having large amount of light are preferablyarranged along a straight line which is parallel to the first axis andwhich passes through the optical axis of the illumination system.

Furthermore, a center area of the three areas having large amount oflight is preferably set such that an amount of light of a center partthereof is smaller than an amount of light of a part other than thecenter part. Whereby, it is able to increase the resolution in thedirection of which the pattern is isolated and to widen the depth offocus.

In this case, the center area is around an annular zone area as anexample. Furthermore, the center area comprises a plurality of areasseparated from each other. The plurality of areas separated from eachother, which are the center area, are arranged along a predeterminedstraight line passing through the optical axis of the illuminationsystem on the predetermined plane as an example. Furthermore, anarranging direction of the plurality of areas separated from each other,which are the center area, is determined according to a size of thecenter area as another example.

Further, the three areas have outlines which are the substantially samewith each other as an example. Further, the sizes of the three areashaving large amount of light respectively correspond to 0.1 times 0.2times of a maximum a value of the illumination system. Whereby, the deepdepth of focus is obtained according to the simulation of the presentinvention.

Furthermore, the two areas of the three areas having large amount oflight, which are arranged at both ends with respect to the directionparallel to the first axis, may respectively have longitudinaldirections which are substantially coincident with a direction parallelto the second axis. Whereby, it is able to enhance the resolutioncorresponding to the one directional high density pattern and to avoidthe reduction of the amount of light.

Further, the center area of the three areas having large amount of lightmay have a longitudinal direction which is substantially coincident withthe direction parallel to the first axis.

Furthermore, an optical beam generated from a center area of the threeareas having large amount of light may linear polarization, a directionsof polarization is substantially coincident with a direction parallel tothe first axis.

Furthermore, an optical beam generated from a center area of the threeareas having large amount of light and optical beams generated from theother two areas may have different polarization states from each other.In this case, a polarization direction of the optical beam generatedfrom the center area and a polarization direction of the optical beamsgenerated from the other two areas are orthogonal to each other.

Further, a size of the center area of the three areas having greatamount of light and sizes of the other two areas may be different fromeach other.

Further, the optical beams generated from the other two areas except forthe center area of the three areas having large amount of light may berespectively linear polarization. In this case, for an example, thedirections of polarization of optical beams distributed in the other twoareas on the predetermined plane may be respectively substantiallycoincident with a circumference direction (that is, the optical beam maybe S polarization).

Further, for an example, the predetermined plane is a pupil plane of theillumination system. Furthermore, as another example, a predeterminedplane is the conjugate plane for the pupil plane of the illuminationsystem or the pupil of the projection system (or its conjugate plane).In this case, it is obtained the highest resolution.

Next, the first exposure apparatus according to the present invention,in an exposure apparatus which an illumination system illuminates a maskwith an optical beam; and a projection system which exposes a substratewith the optical beam from the mask, characterized by comprising anoptical member which sets a light amount distribution of the opticalbeam on a predetermined plane with respect to the illumination systemsuch that an amount of light is set larger in nine areas than in an areaother than the nine areas, the nine areas including a first area andeight areas, an outer contour of the first area including an opticalaxis of the illumination system, and the eight areas being arranged soas to encompass the first area and each of the eight areas being smallerthan the first area.

According to the present invention, with the optical members, it is ableto simultaneously transfer patterns having various kinds of pitch withhigh resolution respectively.

In this case, in order to more improve the resolution and the depth offocus, it is preferable that the central first area is an annular zonearea.

Furthermore, as an example, the predetermined plane is a pupil plane ofthe illumination system, and the nine areas in which the amount of lightat the predetermined plane is greater than the amount of light at thearea other than the nine areas, comprises the first area, four secondareas which are arranged along a first circumference that encloses thefirst area and which are respectively smaller than the first area, andfour third areas which are arranged along a second circumference thatencloses the first circumference and which are respectively smaller thanthe first area.

Furthermore, it is preferable that the first area, the two second areas,and two of the third areas are arranged along a first straight linepassing through the optical axis of the illumination system, and thefirst area, the other two of the second areas, and the other two of thethird areas are arranged along a second straight line which isorthogonal to the first straight line and which passes through theoptical axis of the illumination system.

Also in this case, the size of each area preferably satisfies theconditions of the equations (1) to (3).

Next, the second exposure apparatus according to the present invention,in an exposure apparatus which an illumination system which illuminatesa mask with an optical beam; and a projection system which exposes asubstrate with the optical beam from the mask, characterized bycomprising an optical member which sets a light amount distribution ofthe optical beam on a predetermined plane with respect to theillumination system such that an amount of light is set larger in fiveareas than in an area other than the five areas, the five areasincluding a first area of an annular zone shape and four areas, an outercontour of the first area including an optical axis of the illuminationsystem, and the four areas being arranged so as to encompass the firstarea and each of the four areas being smaller than the first area.

According to the present invention, with the optical members, it is ableto simultaneously transfer patterns having various kinds of pitch withhigh resolution respectively.

Further, as an example, the predetermined plane is a pupil plane of theillumination system, and the five areas in which the amount of light onthe predetermined plane is greater than the amount of light at the areaother than the five areas, comprises the first area and four secondareas which are arranged, at intervals of substantially 90 degreetherebetween, along a circumference that encloses the first area andwhich are respectively smaller than the first area.

Also in this case, the size of each area preferably satisfies theconditions of the equations (1) to (3).

Furthermore, as an example, the illumination system includes an opticalintegrator which substantially uniformize illuminance within anilluminant area on the mask on which the optical beam is irradiated, andthe optical member is arranged at an incident side of the opticalintegrator in the illumination system, and the optical member includes adiffractive optical element which diffracts the optical beam to aplurality of directions. In particular, with using a phase typediffractive optical element, it is able to obtain high use-efficiency.

Furthermore, as another example, the illumination system includes anoptical integrator which substantially uniformize illuminance within anilluminant area on the mask on which the optical beam is irradiated, andthe optical member is arranged on the predetermined plane or a conjugateplane thereof, and the optical member includes an aperture stop definingan area in which an amount of light is enhanced on the predeterminedplane. The aperture stop has a simple structure and can easily set thepreferable distribution of the amount of light.

Further, the optical member can preferably set different plural lightamount distributions including a distribution which enhances the amountof light at the plurality of areas. Whereby, it is able to exposevarious kinds of pattern with optimum irradiating condition.

In the exposure apparatus according to the present invention also, anoptical beam generated from each of the areas which have large amount oflight and which are arranged out of the optical axis of the illuminationsystem on the predetermined plane may be linear polarization. In thiscase, a direction of polarization of the optical beam on thepredetermined plane may substantially coincident with a circumferencedirection (that is, the optical beam may be S polarization).

Further, as an example, the optical member may further includes apolarization member which generates optical beams respectivelydistributed at different areas on the predetermined plane, and apolarization setting member which sets polarization states of theoptical beams generated from the polarization member in the illuminationsystem.

An example of the polarization member is a diffractive optical elementwhich generates diffracted light to a plurality of directions on anoptical path of the illumination system.

Furthermore, the optical member includes movable members which arearranged at an exit side of the polarization member, and which canchange a positional relation between each area outside the optical axison the predetermined plane and the optical axis of the illuminationsystem, and the polarization setting member may be arranged between thepolarization member and the movable member.

Further, the movable members may include at least one movable prismwhich has an inclined plane through which an optical beam distributed ina predetermined area including a plurality of areas outside the opticalaxis except the first area on the predetermined plane passes, the atleast one movable prism moves along the optical axis of the illuminationsystem.

Further, the optical member includes at least one movable prism whichcan change positions of a plurality of areas which enclose the firstarea and which have greater amount of light than an area other than theplurality of areas. The movable prism, as an example, has an inclinedplane through which an optical beam distributed in a predetermined areaincluding a plurality of areas outside the optical axis except the firstarea on the predetermined plane passes, and the movable prism movesalong the optical axis of the illumination system. Furthermore, themovable prism, as another example, has a flat plane through which anoptical beam distributed in the first area passes and which isapproximately orthogonal to the optical axis of the illumination system.

Next, the third exposure apparatus according to the present invention,in an exposure apparatus which an illumination system illuminates a maskwith an optical beam; and a projection system which exposes a substratewith the optical beam from the mask, characterized by comprising anoptical member which sets a light amount distribution of the opticalbeam on a predetermined plane with respect to the illumination systemsuch that an amount of light is set larger in a first area and aplurality of areas than in an area other than the first area and theplurality of areas, the first area substantially including an opticalaxis of the illumination system, and the plurality of areas beingarranged outside the first areas, wherein the optical member includes apolarization member which generates optical beams respectivelydistributed at different areas on the predetermined plane, and at leastone movable prism having a flat plane through which an optical beamgenerated from the polarization member and distributed in the first areapasses and which is approximately orthogonal to the optical axis of theillumination system and an inclined plane through which an optical beamdistributed in a predetermined area including a plurality of areasoutside the optical axis except the first area passes, to change apositional relation between each area outside the optical axis on thepredetermined plane and the optical axis of the illumination system.

According to the present invention, with the diffractive optical member,it is able to simultaneously transfer pattern having various kinds ofpitch with high resolution respectively. Further, with the movableprism, it is able to adjust the characteristic of the image-formingaccording to the kind of the pattern to be transferred.

In the present invention, as an example, the illumination systemincludes an optical integrator which substantially uniformizeilluminance within an illuminant area on the mask on which the opticalbeam is irradiated, and the movable prism is arranged at an incidentside of the optical integrator in the illumination system, and themovable prism moves along the optical axis.

Further, optical beams generated from the plurality of areas arrangedoutside the first area are respectively linear polarization (Spolarization) in which the polarization direction thereof beingsubstantially coincident with a circumference direction on thepredetermined plane.

Further, the optical member can preferably set different plural lightamount distributions including a distribution which enhances the amountof light at the plurality of areas including the first area.

Next, the forth exposure apparatus according to the present invention,in an exposure apparatus an illumination system illuminates a mask withan optical beam; and a projection system which exposes a substrate withthe optical beam from the mask, characterized by comprising opticalmembers which set a light amount distribution of the optical beam on apredetermined plane with respect to the illumination system such that anamount of light is set larger in three areas separated from each otherthan in an area other than the three areas.

According to the present invention, with using the optical member, it isable to transfer the one direction dense pattern to the two directionsof the isolated and periodical ones with high resolution.

In this case, the three areas having large amount of light preferablyinclude a first area near an optical axis of the illumination opticalsystem, and a second area and a third area which are arranged along astraight line passing through the optical axis so as to sandwich thefirst area. Alternatively, the three areas having large amount of lightmay include a first area near an optical axis of the illuminationoptical system, and a second area and a third area which are arrangedwith the approximately same distance from the optical axis.

In these compositions, if a first axis direction in which a high densitypattern formed on the mask is periodically arranged and a second axisdirection in which the high density pattern is arranged substantiallyisolatedly, the second axis direction being orthogonal to the first axisdirection, the three areas having large amount of light are arrangedwith a distance therebetween in a parallel direction to the first axisdirection. Whereby, it is able to transfer the one direction densepattern with high resolution along the first axis and the second axisrespectively. Further, the three areas having large amount of light arearranged along a straight line which passes through the optical axis ofthe illumination system and which is parallel to the first axis.

Further, a center area of the three areas having large amount of lightis set such that an amount of light of a center part thereof is smallerthan an amount of light of a part other than the center part. Whereby,it is able to increase the resolution in the direction of which thepattern is isolated and to widen the depth of focus.

In this case, the center area is substantially an annular zone area asan example. Furthermore, the center area comprises a plurality of areasseparated from each other as another example. The plurality of areasseparated from each other, which are the center area, are arranged alonga predetermined straight line passing through the optical axis of theillumination optical system on the predetermined plane as an example.Furthermore, an arranging direction of the plurality of areas separatedfrom each other, which are the center area, is determined according to asize of the center area as another example.

Further, the sizes of the three areas having large amount of lightrespectively correspond to 0.1 times to 0.2 times of a maximum σ valueof the illumination system. Whereby, the deep depth of focus is obtainedaccording to the present invention.

Further, in the present invention, two areas of the three areas havinglarge amount of light, which are arranged at both ends with respect tothe direction parallel to the first axis, respectively have longitudinaldirections which are substantially coincident with a direction parallelto the second axis.

Further, a center area of the three areas having large amount of lighthas a longitudinal direction which is substantially coincident with thedirection parallel to the first axis.

Further, an optical beam generated from a center area of the three areashaving large amount of light is linear polarization, a directions ofpolarization is substantially coincident with a direction parallel tothe first axis.

Further, an optical beam generated from a center area of the three areashaving large amount of light and optical beams generated from the othertwo areas may have different polarization states from each other. Inthis case, as an example, a polarization direction of the optical beamgenerated from the center area and a polarization direction of theoptical beams generated from the other two areas are orthogonal to eachother.

Further, a size of the center area of the three areas having greatamount of light and sizes of the other two areas may be different fromeach other.

Further, optical beams generated from the other two areas except for thecenter area of the three areas having large amount of light arerespectively linear polarization. In this case, as an example,directions of polarization of optical beams distributed in the other twoareas on the predetermined plane are respectively substantiallycoincident with a circumference direction (S polarization).

Further, as an example, the optical member includes a polarizationmember which generates optical beams respectively distributed atdifferent areas on the predetermined plane, and the exposure apparatusfurther comprises a polarization setting member which sets polarizationstates of the optical beams generated from the polarization member inthe illumination system. In this case, further, the optical memberincludes a movable member which is arranged at an exit side of thepolarization member, and which can change a positional relation betweenthe other two areas except for the center area of the three areas havinglarge amount of light and the optical axis of the illumination system,and the polarization setting member is arranged between the polarizationmember and the movable member.

Further, the movable member includes at least one movable prism whichhas an inclined plane through which an optical beam distributed in apredetermined area including the other two areas except for the centerarea on the predetermined plane passes, and the at least one movableprism moves along the optical axis of the illumination system.

Further, the optical member may include at least one movable prism whichcan change positions of the other two areas except for the center areaof the three areas having large amount of light. In this case, themovable prism, as an example, has an inclined plane through which anoptical beam distributed in a predetermined area including the other twoareas except for the center area on the predetermined plane passes, andthe movable prism moves along the optical axis of the illuminationsystem.

Further, the movable prism, as another example, may have a flat planethrough which an optical beam distributed in the center area on thepredetermined plane passes and which is approximately orthogonal to theoptical axis of the illumination system. Further, as an example, theillumination system includes an optical integrator which substantiallyuniformize illuminance within an illuminant area on the mask on whichthe optical beam is irradiated, and the movable prism is arranged at anincident side of the optical integrator in the illumination system.

Further, a predetermined plane is, as an example, a pupil plane of theillumination system. In this case, the illumination system, as anexample, includes an optical integrator which substantially uniformizeilluminance within an illuminant area on the mask on which the opticalbeam is irradiated, and the optical members include a diffractiveoptical element which is arranged at an incident plane side of theoptical integrator in the illumination system. With this constitution,it is able to obtain a high efficiency.

Further, as another constitution of a predetermined plane being thepupil plane, the illumination system includes an optical integratorwhich substantially uniformize illuminance within an illuminant area onthe mask on which the optical beam is irradiated, and the optical memberis arranged on the predetermined plane or a conjugate plane thereof, andthe optical member includes an aperture stop defining the three areas.With this constitution, it is easily able to make the distribution ofthe amount of light at a predetermined plane desirable distribution.

Further, the optical members can preferably set different plural lightamount distributions including a light amount distribution whichenhances the amount of light in the three areas. Whereby, it is able totransfer various kinds of patterns with high resolution.

Next, method for fabricating device according to the present inventionis method for fabricating device including lithography process in whichpatterns are transferred to the photosensitive material by using theexposure method or apparatus according to the present invention. Withthe exposure method or apparatus according to the present invention, themass production of devices including various kinds of patterns or onedirection pattern with high accuracy.

EFFECTS OF THE PRESENT INVENTION

In the present invention, when setting the distribution of apredetermined plane relating to the illumination system so as toincrease the amount of light at a predetermined nine or five areas, itis able to simultaneously transfer patterns having various kinds ofpitches with high resolution respectively.

Further, by making the center first area annular, it is able to moreimprove the resolution and depth of focus. Furthermore, by controllingthe state of polarization of the optical beam, it might be able to moreimprove the resolution and the like.

Furthermore, in the present invention, when setting the distribution ofa predetermined plane relating to the illumination system so as toincrease the amount of light at a predetermined three areas, it is ableto transfer one direction patterns with high resolution.

Furthermore, if the pattern formed at the mask is periodically arrangedalong a predetermined first axis and includes the one direction densepattern which is substantially isolated in the direction of the secondaxis orthogonal to the first axis, by arranging the three areas in whichthe amount of light is great with distance in the parallel direction tothe first axis, it is able to transfer the one direction dense patternwith high resolution both directions of arranging the one directiondense pattern to periodical and isolatable ones. Further, in the presentinvention, with setting the state of polarization of the optical beamoriented from the three areas in which the amount of light is great, itmight be to improve the resolution and the like for a predeterminedpattern.

BRIEF DESCRIPTION OF THE FIGURES IN THE DRAWINGS

FIG. 1A shows a composition of a projection exposure apparatus of thefirst embodiment according to the present invention, FIG. 1B shows anenlarged perspective view of prism 71, 72 of FIG. 1A, FIG. 1C showsother example composition of prism 71, 72;

FIG. 2 is a plan view showing an example pattern of reticle R;

FIG. 3 shows the distribution of amount of light to be set bydiffractive optical element 21 on the exit plane (pupil plane) of thefly' eye lens 5, which includes the amount of light in nine areas;

FIG. 4 shows the distribution of amount of light becoming large in fiveareas on the exit plane (pupil plane) of the fly' eye lens 5;

FIG. 5 shows an evaluating result through simulation of the transferredimage when exposure is made with the distribution of amount of light ofFIGS. 3 and 4;

FIG. 6A shows a modified example of assuming the center of the area tobe annular, in the distribution of amount of light of FIG. 3, and FIG.6B shows another modified example of the amount of light of FIG. 3;

FIG. 7A shows a distribution of amount of light in which the amount oflight becomes large in five areas including the center of the annulus tobe set by the diffractive optical element 22 on the exit plane (pupilplane) of the fly' eye lens 5, and FIG. 7B shows a modified example ofthe distribution of amount of light of FIG. 7A;

FIG. 8 shows an evaluating result through simulation of the transferredimage when exposure is made with the distribution of amount of light ofFIG. 7A;

FIG. 9 shows a modified example for the distribution of amount of lightof FIG. 3;

FIG. 10 shows a modified example of perspective view of the prisms 71and 72 of FIG. 1A;

FIG. 11A is a plan view of one example of the pattern of reticle R1 thatbecomes an object of exposure in the second embodiment of the presentinvention, and FIG. 11B shows a modified example of the pattern ofreticle R1;

FIG. 12 shows a distribution of amount of light, which is set by thediffractive optical element 22A of FIG. 1A on the exit plane (pupilplane) of the fly' eye lens 5 in the second embodiment of the presentinvention;

FIG. 13A shows optical beams diffracted in the Y direction by thepattern 52 of FIG. 11A, and FIG. 13B shows optical beams diffracted inthe X direction by the pattern 52 of FIG. 11A;

FIG. 14 shows an evaluating result of depth of focus (DOF) throughsimulation of the transferred image when exposure is made with thedistribution of amount of light of FIG. 12;

FIG. 15A, FIG. 15B, and FIG. 15C respectively show a modified examplefor the distribution of amount of light FIG. 12;

FIG. 16A shows the distribution of amount of light to be set by thediffractive optical element 22B of FIG. 1A on the exit plane (pupilplane) of the fly' eye lens 5, and FIG. 16B shows a modified example ofthe distribution of amount of light of FIG. 16A;

FIG. 17 shows an evaluating result of depth of focus (DOF) throughsimulation of the transferred image when exposure is made with thedistribution of amount of light of FIG. 16A;

FIG. 18 shows a composition of a projection exposure apparatus of thethird embodiment according to the present invention;

FIG. 19 shows a pattern of the aperture stop 42 of FIG. 18;

FIG. 20 shows a pattern of the aperture stop corresponding to thedistribution of amount of light of FIG. 6;

FIG. 21 shows a pattern of the aperture stop corresponding to thedistribution of amount of light of FIG. 7A;

FIG. 22A and FIG. 22B respectively show a pattern of the aperture stop42A and 42B of FIG. 18;

FIG. 23 shows a main part of the illumination system of the fifthembodiment according to the present invention; and

FIG. 24 shows an example of the process for fabricating thesemiconductor device using the projection exposure apparatus of theembodiment according to the present invention.

BEST MODE FOR CARRYING OUT OF THE INVENTION The First Embodiment

A preferably first embodiment will be described accompanying FIGS. 1 to9, as follows:

This embodiment applies the present invention when doing exposure withthe projection exposure apparatus using an illumination system which hasa fly' eye lens as an optical integrator (uniformizer or homogenizer).

FIG. 1A shows a composition of the projection exposure apparatus of thisembodiment, in FIG. 1A, a KrF excimer laser light source (wave-length248 nm) is used as an exposure light source 1. In addition, the laserlight sources such as an ArF excimer laser light source (wave-length 193nm), a F₂ laser light source (wave-length 157 nm), a Fr₂ laser lightsource (wave-length 146 nm), or an Ar₂ laser light source (wave-length126 nm); or high frequency generating apparatus such as a high frequencygenerating light source of a YAGI laser or a solid laser (for examplesemiconductor laser etc.) can be used as an exposure light source 1.

An illumination light L1 comprised of ultraviolet pulse light as anoptical beam for exposure (exposure beam) emitted from exposure lightsource 1 goes into the first diffractive optical element 21 through anoptical path folding miller 3, after changing the cross-sectional shapeof the optical beam into the desirable shape with beam expander 2, andis changed the optical beam DL which diffracts to the plural directionsin order to be obtained a predetermined distribution of amount of lightat a predetermined plane (for example pupil plane of the illuminationsystem) as described after. The diffractive optical element 21 as a partof the optical member for setting distribution of amount of light ismounted to a revolver 24, the second diffractive optical element 22having other diffractive characteristic and further, diffractive opticalelement (not shown) having another diffractive characteristic are alsomounted. In this embodiment, a main control system 17 controlling overthe all operation of the apparatus controls the revolving angle of therevolver 24 through a driver 23, by setting one of the diffractiveoptical element 21 and 22 etc. on the optical path of the illuminationlight L1, can change the condition of illumination.

In FIG. 1A, the optical beam DL diffracted by the diffractive opticalelement 21 is gathered by a relay lens 4, is gathered on an incidentplane of the fly' eye lens 5 as an optical integrator, through a firstprism 71 and a second prism 72 (movable prism). In this case, thediffractive optical element 21 is arranged at a position slightlydeviated from a front focus of the relay lens 4 to the exposure lightsource 1 than, and the incident plane of fly' eye lens 5 isapproximately arranged at the position of the back focus of the relaylens 4. Furthermore, a plurality of optical beams diffracted to thedifferent directions are respectively gathered at the different areas onthe incident plane of the fly' eye lens 5, a plane light source(2-dimentional light source comprised of many light source images inthis embodiment) of distribution approximately corresponding to theamount of light of the incident plane is formed. With a combined lenssystem comprised of the relay lens 4 and fly' eye lens 5, the exit planeof the diffractive optical element 21 and the exit plane Q1 of the fly'eye lens 5 have approximately be conjugate (imaging relation).

In this embodiment, the diffractive optical element 21, the first prism71, and the second prism 72 are corresponding to an optical member forsetting a predetermined distribution of amount of light. As shown inFIG. 1B, the first prism 71 is a member which forms a parallel flatplate 71 at circular area of which the center is an optical axis BX(discuss later) of a illumination system, and forms a concave cone 71 baround the circular area; the second prism 72 is a member which formsinverted concave and convex for the first prism 71, and forms a parallelflat plate as a whole by combining with the first prism 71. In addition,a optical beam passing the circular area of the center of the firstprism 71 and the second prism 72 (that is the optical beam traveling ina straight line along the optical axis BX within the first prism 71 andthe second prism 72) distributes to areas which are a center of adistribution of amount of light on the exit plane Q1 on the fly' eyelens 5 in which amount of light is enhanced; a optical beam passing thecone part (slope plane) around the first prism 71 and the second prism72 distributes to a plurality of areas (or a predetermined areaincluding the plurality of areas) in which amount of light is enhancedaround the distribution of amount of light.

Further, at least one of the first prism 71 and the second prism 72, forexample in this embodiment, the second prism 72 is only supportedmovably by a driving mechanism (not shown), thus by changing thedistance between the first prism 71 and the second prism 72 by movingthe second prism 72 along the optical axis BX, the position of aplurality of peripheral areas in which the amount of light is great canadjust to the radial direction, without changing the centraldistribution (position of areas 28, 33 etc. described below) of thedistribution of amount of light at the exit plane Q1 on the fly' eyelens 5.

In addition, a prism having not a cone but a pyramid may be used insteadof the first prism 71 and the second prism 72. Furthermore, it is allowmoving this position along the optical axis BX by only using the firstprism 71 instead of the first prism 71 and the second prism 72. Further,as shown in FIG. 1C, it is allow using a pair of prisms 71A, 71B shapedlike a letter V which has diffractive power to one direction and has notdiffractive power to orthogonal direction, as the movable prism. Inaddition, the prisms 71A, 71B are arranged so that each rectangle area(in this embodiment, the parallel flat plate) of its center isapproximately orthogonal to the optical axis BX and two slope planes ofthe around area are approximately symmetric with respect to a planebeing orthogonal to the paper of FIG. 1C including the optical axis BX.

With this composition, by changing the distance between the prisms 71A,71B, positions (distance from the optical axis BX) of a peripheral area,in which amount of light is great, concerning the above and belowdirection of the paper in FIG. 1C (e.g., corresponding to a Y directionin FIG. 3 showing a distribution of amount of light of an illuminationlight at a pupil plane of an illumination system 12) changes. Therefore,in order to adjust positions (distance from the optical axis BX) of aperipheral area, in which amount of light is great, concerning theorthogonal direction to that position (the orthogonal direction to thepaper in FIG. 1C, corresponding to an X direction in FIG. 3), anotherpair of prisms 71C, 71D constructed by revolving the pair of prisms 71A,71B by 90 degrees about the optical axis BX may be arranged. Whereby, itis able to independently adjust each position (distance from the opticalaxis BX) being orthogonal each other in which amount of light is great.

In addition, however the prism described above whose slope plane is thecone, pyramid, or shaped like a letter V the center flat plate is theparallel flat plate, it may be aperture part (hollow part) by cutting atlest one part of the center part, or may be an integral solid by makinga plurality of members independently. In particular, the latter may bean integral solid by only dividing the peripheral slope plate except thecenter flat plate part into a plurality of parts.

In FIG. 1A, however if it is not necessary to change the position ofperipheral area in which the amount of light is great to the radialdirection, the first prism 71 and the second prism 72 can be omitted.

In addition, the fly' eye lens 5 is, as an example, a bundle of manylens elements each of which has a rectangular cross-section whosevertical and horizontal width is about a few of millimeter, the shapecross-section of each lens element is approximately similar to a slimpiece of illumination area on a reticle. However, a micro fly' eye lensconstructed by binding many micro lenses whose shape cross-section isrectangular with about a few tens of micrometer or circular withdiameter of about a few tens of micrometer can be used.

The illumination light L1 comprises optical beam emitted from the fly'eye lens 5 is one time gathered on the plane Q2 by a condenser lenssystem 6. A fixed field stop (fixed blind) 7 for limiting anillumination area on a reticle R as an illuminated target to a slimshape orthogonal to scan direction, i.e., not-scan direction is arrangedat slight front side of the plane Q2, a movable field stop (movableblind) 8 on the plane Q2. The movable field stop is used to prevent fromuseless exposure by controlling the width of the scan direction of theillumination area at the front and back of the scan exposure, and tolimit the width of the not-scan direction of the illumination areaduring the scan exposure. As an example, a reticle stage driving system16 described bellow controls open/close operation of the movable fieldstop 8 through a driving section 13 in sync with operation of thereticle stage.

The illumination light L1 passing through the field stop 7 and 8, via aimaging-lens system 9, optical path folding miller 10, and maincondenser lens system 11, illuminates a slim illumination area on acircuit pattern area of a pattern plane (it will be called “reticleplane” hereinafter) of the reticle R as a mask with even intensitydistribution. An illumination system 12 is composed of the exposurelight source 1, a beam expander 2, the miller 3, the diffractive opticalelement 21 (or other diffractive optical element), the relay lens 4,fly' eye lens 5, the condenser lens system 6, field stop 7, 8, theimaging-lens system 9, the miller 10, and the main condenser lens system11. An optical axis of the illumination system 12 is regarded as theoptical axis BX. In this case, the exit plane Q1 of the fly' eye lens 5is substantially coincident to an optical Fourier transform plane forthe pupil plane of the illumination system 12, i.e., reticle: the planeQ2 in which the movable field stop 8 is arranged is a conjugate planewith the reticle plane. In addition, the fixed field stop 7, forexample, may be arranged near the reticle plane.

Under the illumination light L1, the imaging-circuit patterns withinillumination area of the reticle R, via a projection optical system PLof both side telecentric as a projection system, transfers a resistlayer of one shot area among a plurality of shot areas on a wafer W as asubstrate arranged on an image-forming plane of the projection opticalsystem PL with a predetermined downsizing magnification β (for example,β is ¼, ⅕ etc.). In addition, the reticle R and wafer W is respectivelyregarded as a first object and second object. Furthermore, the wafer Was substrate for exposure is a circular substrate such as semiconductor(silicon etc.) or SOI (silicon on insulator) whose diameter is 200 or300 mm, for example.

An optical axis AX of the projection optical system PL is coincident toan optical axis BX of the illumination system on the reticle R.Furthermore, a pupil plane Q3 (optical Fourier transform plane for thereticle plane) on the projection optical system PL is conjugate with theexit plane Q1 (the pupil plane of the illumination system 12) of thefly' eye lens 5. As the projection optical system PL of this embodiment,other one except the diffractive system can be used, for example, acatadioptric projection optical system having a plurality of opticalsystems having optical cross-axes each other as disclosed in JapanesePatent Application: TOKUKAI 2000-47114 (corresponding to U.S. Pat. No.6,496,306) or, for example, a catadioptric projection optical system andthe like which has an optical system including an optical axis intendsfrom a reticle to a wafer and a catadioptric optical system including anoptical axis being approximately orthogonal to that optical axis, andwhich forms an intermediate image twice in its interior as disclosed ininternational publication (WO): 01/065296 brochure (corresponding to USpublication 2003/0011755A1). It will be described the projection opticalsystem PL, with considering that a Z axis is paralleled to the opticalaxis AX, a X axis is not-scan direction (the direction parallel to thepaper in FIG. 1A, in this case) orthogonal to the scan direction, and aY axis is the scan direction (the direction orthogonal to the paper inFIG. 1A, in this case), as follows:

First, the reticle R is adsorbed and held on the reticle stage 14; thereticle stage 14 is mounted so as to move with a constant velocity alongthe Y direction on a reticle base 15, and to slightly move alongrotating directions about the X , Y, and Z axis. The position of thereticle stage 14 is measured by a laser interferometer in a reticledriving system 16. The reticle driving system 16 controls the positionand velocity of the reticle stage 14 through driving mechanism notshown, based on the measured information and control information from amain control system 17.

On the other hand, the wafer W is adsorbed and held on a wafer stage 18through wafer holder not shown; the wafer stage 18 is movably mounted inthe X and Y directions on a wafer base 19. The position of the waferstage 18 is measured by a laser interferometer in a wafer driving system20. The wafer driving system 20 controls the position and velocity ofthe wafer stage 18 through driving mechanism not shown, based on themeasured information and control information from the main controlsystem 17. Furthermore, a focusing mechanism for fitting the surface ofthe wafer into the image-forming plane of the projection optical systemPL is assembled in the wafer stage 18 during the scan exposure, based onmeasured information of an auto-focus sensor not shown.

During scan exposure, under controlling of the main control system 17,the reticle driving system 16, and the wafer driving system 20,operation of scanning one shot area on the wafer W to a correspondingdirection (+Y or −Y direction) for the slim exposure area (theillumination area of the illumination light L1 being conjugated with theillumination area concerning projection optical system PL) with velocityβ*VR (β is projection magnification) through the wafer stage 18, andoperation of step-moving the wafer W to the X, Y directions through thewafer stage 18 are repeated, in sync with scanning the reticle R to theY direction for the illumination area illuminated illumination lightwith velocity VR through reticle stage 14.

Next, an illumination system and an illumination method will bedescribed in detail.

FIG. 2 shows an example of a pattern (original pattern) for transferringformed on a reticle R; in FIG. 2, a 2-dimentional pattern with threekinds of contact holes arranging pattern 25A, 25B, and 25C ofapproximate squares with pitch P1, P2, and P3 at the X, Y directions ina pattern region PA of the reticle R. Each pattern 25A, 25B, and 25C maybe a transmission pattern formed in a light shielded film, or mayconversely be a light shielded pattern formed in a transmission part.Furthermore, the width of each pattern 25A, 25B, and 25C is around equalto ½ or smaller than corresponding pitch P1, P2, and P3 respectively,however, the width of pattern 25B, 25C with larger pitch can be aroundequal to pattern 25A with most fine pitch. In this case, the pitch P1,P2, and P3 are set to gradually become several-fold, as follows:P1<P2<P3   (4)

If the projection magnification β of the projection optical system PL inFIG. 1A is ¼-fold, pitch P1, P2, and P3 on the reticle plane arerespectively set, as an example, around 300 nm, 600 nm, and 900 nm. Thatis, the original patterns on the reticle plane include a first patternfor dense contact holes with fine pitch, a second pattern for densecontact holes with around middle pitch, and a third pattern for contactholes arranged with large pitch substantially regarding as the isolatedcontact holes. In order to transfer an image of these original patternson wafer one time with high accuracy, as shown FIG. 1A in thisembodiment, with arranging the diffractive optical element 21 on theoptical path of an illumination light IL, the distribution of amount oflight (strength distribution) of the illumination light IL at the exitplane Q1 (pupil plane) of the fly' eye lens 5 as a predetermined plane.

FIG. 3 shows the distribution of amount of light of the illuminationlight IL at the exit plane Q1 (pupil plane of the illumination system)of the fly' eye lens 5. In this FIG. 3, the direction on the exit planeQ1 corresponding to the X direction and Y direction (i.e., the arrangingdirection of the pattern to transfer) on the reticle R is respectivelydefined the X direction and Y direction. Here, if the numerical apertureof the object side (reticle side) of the projection optical system PL inFIG. 1A is NA, the numerical aperture of the image side (wafer side) isNA_(PL), a relation is obtained with using the projection magnificationβ, as follows:NA=β·NA _(PL)   (5)

Further, it is defined that the maximum value among the numericalapertures of the illumination light IL incident to the reticle R fromthe illumination system 12 is NA_(IL), the value of ratio (coherencefactor) of the maximum numerical aperture NA_(IL) to the numericalaperture NA of the projection optical system PL is called maximum σvalue in this embodiment, and maximum σ value is σ. That is, theillumination light of maximum C value is the light incident on thereticle R with the maximum angle among the illumination light IL. Themaximum σ value (σ) can be expressed, as follows:σ=NA _(IL) /NA=NA _(IL)/(β−NA _(PL))   (6)

In a pupil plane of an illumination system shown in FIG. 3, a maximumouter circle 26 indicates an outer area passed through virtual opticalbeam having the same numerical aperture as the numerical aperture NA atthe incident side of the projection optical system PL, an inner circle27 indicates a circle is tangent to areas passed through illuminationlight having numerical aperture of the maximum σ value (σ); allillumination light pass though within the circle 27. The illuminationlight L1 of this embodiment, in FIG. 3, approximately has a constantamount of light at nine areas with distance each other which include acircular area 28 with radius r1 centered an optical axis BX of theillumination system 12, four circular areas 29A, 29B, 29C, and 29D withradius r2 whose centers are arranged along a first circle 32A withradius R1 enclosing the area 28, and four circular areas 30A, 30B, 30C,and 30D with radius r3 whose centers are arranged along a second circle32B with radius R2 enclosing the areas 29A to 29D, and has distributionof amount of light of lower amount of light (approximate 0 in thisembodiment) at other areas than the constant amount of light. Inaddition, the amount of light, near the outline of the area 28, areas29A to 29D, and areas 30A to 30D, may have distributions which graduallydecrease toward the outside. The center area 28 corresponds to a firstarea; the four areas 29A to 29D enclosing the area 28 correspond tosecond areas; further the four areas 30A to 30D enclosing the areas 29Ato 29D correspond to third areas. Hereinafter, the radii r1 to r3 andR1, R2 respectively indicates the length (distance between point passedthrough the optical beam of the maximum σ value and the optical axis BX)corresponding the maximum σ value (σ) as unit.

First, the center area 28 is set larger than other eight areas 29A to29D and 30A to 30D (r1>r2>r3). Further, since the arranging directionsof the 2-dimensional patterns as the targets to transfer are the Xdirection and Y direction, it is defined that a straight line crossed tothe X direction by 45 degrees in clock winding is a straight line 31A; astraight line (the straight line crossed to the X direction by 45degrees in counter clock winding) is a straight line 31B. Furthermore,the center of the center area 28, the middle two areas 29A and 29C, andother most outer two areas 30A and 30C is arranged on the first straightline 31A; the center of the center area 28, the middle other two areas29B and 29D, and other most outer two areas 30B and 30D is arranged onthe second straight line 31B. That is, the eight areas 29A to 29D and30A to 30D enclosing the center area 28 are arranged along the twodirections being orthogonal with revolving the two arranging directionsby 45 degrees, which are orthogonal, in which patterns as the targetsfor transfer.

Further, as an example, the radius r1 of the area 28, the radii r2 ofthe areas 29A to 29D, and the radii r3 of the areas 30A to 30D are set0.3-fold, 0.1-fold, and 0.1-fold of the maximum σ value (σ) (the radiusof circle 27, after being similar to this), as follows:r1=0.3σ  (7)r2=r3=0.1σ  (8)

Further, the radius R1 of the first circle 32A and the radius R2 of thesecond circle 32B are set 0.55-fold and 0.9-fold of the maximum σ value(σ), as follows:R1=0.55σ  (9)R2=0.9σ  (10)

In this case, the radial distance d1 between the outer of the area 28and the first circle 32A, and the radial distance d2 between the firstcircle 32A and the second circle 32B are as follows:d1=0.25σ, d2=0.35σ  (11)

In this case, the diffractive characteristic of the diffractive opticalelement 21 in FIG. 1A is set, so as to obtain the distribution of amountof light in which the amount of light approximately becomes constant atthe area 28, the areas 29A to 29D, and the areas 30A to 30D in FIG. 3satisfying the condition of the equations (7) to (10): approximatelybecomes 0 at other areas. For the reason, the diffractive opticalelement 21, as an example, can fabricate by forming a concave and convexgrating having approximately systematically along in the direction ofthe straight line 31A, and a concave and convex grating havingapproximately systematically along in the direction of the straight line31B of FIG. 3. Alternatively, the diffractive optical element 21 may bea combination of a plurality of phase type diffractive gratings. Inthese cases, since the diffractive optical element 21 is phase type, itis advantage of high efficiency for using light. In addition, it is ableto use an optical element changing refractive index distributioncorresponding to a diffractive grating distribution as an opticalelement 21. In addition, a construction and a method for fabricatinghaving a specific diffractive characteristic is closely disclosed, forexample, in, Japanese Patent Application: TOKUKAI 2001-176766(corresponding to U.S. Pat. No. 6,563,576) by this applicant.

In addition, with setting the distribution of amount of light obtainedby the diffractive optical element 21 to around constant amount of lightat the areas including the area 28, the areas 29A to 29D, and the areas30A to 30D in FIG. 3, the aperture stop, whose aperture is formed at thepart corresponding to the area 28, the areas 29A to 29D, and the areas30A to 30D in FIG. 3, may be arranged at the exit plane Q1 (pupil plane)of the fly' eye lens 5 or its conjugate plane. Also in this case, it isadvantage of high efficiency for using the illumination light L1.

For this embodiment, this inventor have evaluated the CD (criticaldimension), through the simulation of the computer, which is obtained bytransferring a downsizing image of pattern of contact holes with variouskinds of pith arranged on the reticle plane to the wafer through theprojection optical system PL, under the distribution of amount of lightin which the amount of light becomes constant at the nine areascomprising the area 28, the areas 29A to 29D, and the areas 30A to 30Din FIG. 3 satisfying the condition of the equations (7) to (10): becomes0 at the other areas. The CD used is the line width of patternstransferred. In addition, as this simulation, the numerical apertureNA_(PL) of the image side (wafer side) of the projection optical systemPL in FIG. 1A is 0.82, projection magnification β is ¼-fold, and themaximum σ value (σ) is 0.9, as follows:NA=0.82, β=¼, σ=0.9   (12)

The curve 36 in FIG. 5 shows the simulation result of the CD value incase that the amount of light becomes constant at the nine areas on thepupil plane, the horizontal axis is the pitch (nm) of the patterntransferred on the reticle plane, vertical axis is the CD value (nm) inFIG. 5. The pitch 280 to 1120 nm is equivalent of 70 to 280 nm at thewafer side. As shown in the curve 36, with using the distribution ofamount of light in this embodiment, the preferable CD value havingapproximately constant across the wide range of pitch 280 to 1120 nm.

Accordingly, with using the distribution of amount of light on the pupilplane in FIG. 3 in this embodiment, the patterns of the reticle Rincluding three kinds of pitch in FIG. 2 can one time transfer on thewafer with high accuracy.

In addition, the distribution of amount of light on the pupil plane inFIG. 3 is not satisfied the condition of the equations (7) to (10), theradius r1 of the area 28, the radii r2 of the areas 29A to 29D, and theradii r2 of the areas 30A to 30D may be the ranges, as follows:0.2σ≦r1≦0.4σ  (13)0.075σ≦r2≦0.2σ  (14)0.075σ≦r3≦0.2σ  (15)

Further, the radius R1 of the first circle 32A and the radius R2 of thesecond circle 32B may be changed up to around ±10% of the equations (9)and (10). Furthermore, the numerical aperture NA_(PL) of the image side,the projection magnification β, and the maximum σ value (σ) in theprojection optical system PL can be taken any values though the valuesdescribed above. For example, in order to control the maximum σ value(σ), by changing the distance between prism 71 and 72 in FIG. 1A, theradial position of the areas 29A to 29D, and the areas 30A to 30D withperipheral area in which the amount of light is great among thedistribution of amount of light in FIG. 3 (the distance from the opticalaxis BX relating to the X direction and Y direction) may only bechanged. Alternatively, as shown in FIG. 1C, by using two pairs of prism71A, 71B and 71C, 71D, the position of the areas 29A to 29D, and theareas 30A to 30D with peripheral area in which the amount of light isgreat among the distribution of amount of light in FIG. 3 (the distancefrom the optical axis BX) in the X direction and Y direction mayindependently controlled.

In addition, about the distribution of amount of light in FIG. 3, theamount of light of the center area 28 (e.g., intensity per unit size)and that of the areas 29A to 29D, and the areas 30A to 30D may bedifferent. Furthermore, the amount of light of the four areas 29A to 29Dalong the peripheral first circle 32A and that of the four areas 30A to30D along the peripheral second circle 32B may be different. Therelative amount of these lights may be adjusted so that the optimumresolution is obtained for each pattern, for example.

Further, instead of the distribution of amount of light in FIG. 3, asshown FIG. 6B, a distribution of amount of light becoming great amountof light of the five areas including four slim areas 130A, 130B, 130C,and 130D which are substantially connected to the radial each two areas29A, 29B, 29C, 29D, 30A, 30B, 30C, and 30D of the radial in FIG. 3respectively and the center area 28 may be used. Also in this case, itis almost able to transfer patterns having various kinds of pitch withhigh resolution. In addition, in FIG. 6B, the amount of light of theconnecting parts of two areas in the radial may around equal to that ofthe two areas, or may be different from that of the two areas, forexample smaller.

In addition, in order to more improve the resolution and depth of focusthan using the amount of light of FIG. 3, an area of annular may be usedinstead of the center area 28 as the first area.

FIG. 6A shows a distribution of amount of light of the illuminationlight L1 on the exit plane Q1 (pupil plane of the illumination system12) of fly' eye lens 5 in FIG. 1A, when the first area is the area ofannular. In FIG. 6A with marking the same notes to the partscorresponding to in FIG. 3, the amount of light of the area 28R ofannular consist of the outer radius r1, the inner radius r1R, and thecenter of the optical axis BX and that of the nine areas including thearea 28, the areas 29A to 29D, and the areas 30A to 30D areapproximately constant; and amount of light of the illumination light atthe other areas is approximately 0. Furthermore, the value of ratio ofthe outer radius r1 and inner radius r1R (=r1R/r1) of the annular zonearea 28R is any value between 0 and 1, as an example, ⅓ annular(r1R/r1=⅓), ½ annular (r1R/r1=½), ⅔ annular (r1R/r1=⅔) etc. can be used.The condition other than it is the same as that of the case where theamount of light in FIG. 3 is used.

When the amount of light in FIG. 6A is used, the more stabledistribution of CD value can be obtained than the simulation result ofthe CD value represented in the curve 36 of FIG. 5. Further, the morestable CD value can be obtained with wider depth of focus.

Further, in this embodiment, the light distributed at the peripheralareas 29A to 29D, and the areas 30A to 30D in FIG. 6A may be linearpolarization. In this case, as an example, as shown with an arrow markAR, the light distributed at the peripheral areas may be S polarization(vertical direction for the incident plane) whose polarization directionis the tangent direction. Whereby, the resolution etc. for the specificpattern might be enhanced. It is the similar to the case of using thedistribution of amount of light in FIG. 3 or 6B.

In addition, if the light distributed at the peripheral eight or fourareas with area in which the amount of light is great described above isnon-polarization or whose polarization direction is not coincidental tothe circumference direction, for example, with arrangement polarizationsetting member such as ½ wave plate or ¼ wave plate on the optical pathpassed through the lights distributed at each area between diffractiveoptical element 21 (polarization member) and the fly' eye lens 5, theoptical beam is preferably changed into that of the linear polarizationwhose polarization direction is approximately coincident to thecircumference direction. In this case, the polarization setting memberis preferably arranged between one of the plurality of prisms (movablemember) described above which is arranged at the most upstream side(light source side) and incident side, for example the lens 4, or thediffractive optical element 21 and the lens 4. In this case, it is notnecessary to move the polarization setting member in accordance withchange of the diffractive optical element or the traveling direction ofthe optical beam (optical path) depending on modification of thedistance among the plurality of prisms; or not necessary to enlarge thepolarization setting member in expectation of such change.

In addition, in the distribution of amount of light in FIG. 6B, thecenter circular area 28 may be the area of the annular similar to FIG.6A.

Further, the diffractive optical element 21 in this embodiment, however,sets the distribution of amount of light on the pupil plane of theillumination system 12 as a predetermined plane to a predeterminedstate; the predetermined plane may be the pupil plane Q3 of theprojection optical system PL. In this case, if the reticle R is not inexistence due to the diffractive optical element 21, the distribution ofamount of light is set which is approximately constant at the first areaincluding the axis AX and the eight areas enclosing it, and which islower at the other areas.

In addition, in the examples of FIG. 3 and FIG. 6A of this embodiment,the area 28 (or 28R), each of the areas 29A to 29D, and the areas 30A to30D, in which amount of light is approximately constant on the pupilplane, is the circular (or annular) however, each circular (or annular)can be an area of ellipse (ellipse annular). Furthermore, as describedbellow, the area of circular (or annular) can be an area of polygon (orframe shape of polygon), or can be combination of the area of circular(or annular) and the area of polygon.

FIG. 9 shows possible another distribution of amount of light on thepupil plane, as shown FIG. 9, the distribution of amount of light isapproximately constant at the center square (right square or righthexagon etc. is possible) area 28A, four square areas 30E to 30Henclosing it, and lower than it at the other areas. In this case, thepositions and sizes of the areas may be respectively similar to those ofthe area 28, areas 29A to 29D, and the areas 30A to 30D. In addition, ifcorresponding to FIG. 6A, an area of frame type may be used instead ofthe center area 28A in FIG. 9.

Next, a second diffractive optical element 22 having differentdiffractive characteristic is provided to the revolver 24 in FIG. 1A.With setting the second diffractive optical element 22 on the opticalpath of the illumination light IL, distribution of amount of light whichis approximate constant amount of light at the five areas of the exitplane Q1 (pupil plane) of the fly-eye lens 5, and the lower (approximate0 in this embodiment) than it at the other area is obtained.

FIG. 7A shows a distribution of amount of light of the illuminationlight IL on the exit plane Q1 (pupil plane) of fly-eye lens 5 in FIG.1A, when the second diffractive optical element 22 is used. In FIG. 7Awith marking the same notes to the parts corresponding to in FIG. 3, thedistribution of amount of light at five areas with distance each otherincluding an area 33R (first area) of circular annular consist of theouter radius r1, the inner radius r1R, and the center of the opticalaxis BX of the illumination system 12, and four circular areas 34A, 34B,35C, and 35D (second area) arranging along the a circle 35 having radiusR3 with radius r5 and 90 degrees distance enclosing the area 33R isapproximately constant; and is smaller (approximate 0 in thisembodiment) than the constant amount of light. In this case also, theouter outline of the center area 33R is set larger than that of otherfour areas 34A to 34D (r4>r5).

Further, the value of ratio of the outer radius r4 and inner radius r4R(=r4R/r4) of the annular zone area 33R is any value between 0 and 1, asan example, ⅓ annular (r4R/r4=⅓), ½ annular (r4R/r4=½), ⅔ annular(r4R/r4=⅔) etc. can be used. Further, the preferable range of the radiusr4 is similar to that of the radius r1 of the equation (13), and thepreferable range of the radius R3 and radius r5 are similar to that ofthe radius R2 of the equation (10) and radius r2 of the equation (14)respectively.

Further, in this example, since the arranging direction of the2-dimensional pattern is the X direction and Y direction, the outer fourareas 34A to 34D are respectively arranged along the straight lines passthrough the optical axis BX and cross by 45 degrees in the X direction(or Y direction).

Further, as an example, the radius r4 of the area 33R, the radius r5 ofthe areas 34A to 34D, and the radius R3 of the circle 35 arerespectively set 0.2-fold, 0.1-fold, and 0.9-fold of the maximum σ value(σ), as follows:r4=0.3σ, r5=0.1σ  (16)R3=0.9σ  (17)

This inventor has evaluated the CD (critical dimension), through thesimulation of the computer, which is obtained by transferring adownsizing image of pattern of contact holes with various kinds of pitharranged on the reticle plane to the wafer through the projectionoptical system PL, under the distribution of amount of light in whichthe amount of light becomes constant at the five areas comprising thearea 33, and the areas 34A to 34D in FIG. 4 satisfying the condition ofthe equations (16) and (17); becomes 0 at the areas in addition thereto.In addition, as this simulation, the exposure wave length is ArF laserlight, the numerical aperture NA_(PL) of the image side (wafer side) ofthe projection optical system PL in FIG. 1A is 0.78, projectionmagnification β is ¼-fold, and the maximum σ value (σ) is 0.9.

The curves of line graph F1, F2 in FIG. 8 show the simulation result ofthe CD value in case that the amount of light becomes constant at thefive areas on the pupil plane, the horizontal axis is the defocus amountof wafer (μm), vertical axis is the line width (μm) (line width onwafer) of the pattern well transferred as the CD value. Furthermore,approximate flat curve F1 indicates simulation result for the pattern ofcontact holes with line width 140 nm, pitch 220; mountain-shaped curveF2 indicates simulation result for the isolated pattern with line width140 nm. As shown F1, F2, approximately constant CD value with range inwhich the defocus amount is around −0.2 μm to 0.2 μm is obtained.Accordingly, various kinds of pattern from the isolated pattern to thepattern with fine contact holes with high accuracy and wide depth offocus.

In addition, when the distribution of amount of light in FIG. 7A isused, for example, in order to control the maximum σ value (σ), bychanging the distance between prisms 71 and 72 in FIG. 1A, the radialposition (distance from the optical axis BX relating to the X directionand Y direction) of the areas 34A to 34D in which the amount of light isgreat in FIG. 7A may be changed. Alternatively, as shown in FIG. 1C, byusing two pairs of prism 71A, 71B and 71C, 71D, the position (distancefrom the optical axis BX) of the areas 34A to 34D with peripheral areain which the amount of light is great among the distribution of amountof light in FIG. 7A in the X direction and Y direction may independentlycontrolled.

Further, about the distribution of amount of light in FIG. 7A, it can beset the amount of light of the center area 33R (e.g., intensity per unitsize) and that of the peripheral four areas 34A to 34D differ. Therelative amount of these lights may be adjusted so as to be obtained theoptimum resolution at each pattern for example.

Further, instead of the distribution of amount of light in FIG. 7A, asshown FIG. 7B, a distribution of amount of light becoming great amountof light of the area 134 which is a starfish shape having an aperture atthe center or a star shape substantially connected the four areas 34A to34D and the center annular zone area 33R in the radial direction may beused. The amount of light of the central part of the area 134 may be not0 only smaller. Also in this case, it is almost able to transferpatterns having various kinds of pitch with high resolution.

In addition, when, in FIG. 7A, the peripheral areas 34A to 34D and thecenter area 33R are connected in FIG. 7B, the amount of light of theconnected part getting longer to radial direction may be around equal tothose of the peripheral and center areas, or may be different fromthose, for example smaller than those.

Further, in this example, the light distributed at the peripheral areas34A to 34D in FIG. 7A may be linear polarization. In this case, as anexample, as shown with an arrow mark AR, the light distributed at theperipheral areas may be S polarization (vertical direction for theincident plane) whose polarization direction is the tangent direction.Whereby, the resolution etc. for the specific pattern might be enhanced.It is the similar to the case of using the distribution of amount oflight in FIG. 7B. The light distributing the peripheral area gettinglonger to the radial direction, particularly its part corresponding tothe peripheral areas 34A to 34D in FIG. 7A may be the linearpolarization whose polarization becomes the tangent direction. Inaddition, if the light distributed at the peripheral areas isnon-polarization or whose polarization direction is not coincidental tothe circumference direction, as described above, for example, it ispreferable to provide polarization setting member between thediffractive optical element 21 and the fly-eye lens 5.

In order to compare, the simulation result in which the amount of lightis set constant at a circular area instead of the center annular zonearea 33R in FIG. 7A is represented.

FIG. 4 shows the distribution of amount of light in which the amount oflight is set constant at a circular area 33 instead of the centerannular zone area 33R in FIG. 7A, and the amount of light is setconstant at four areas 34A to 34D enclosing it as with FIG. 7A.

In FIG. 4, as an example, the radius r4 of the area 33, the radii r5 ofthe areas 34A to 34D, and the radius R3 of the circle 35 arerespectively set 0.2-fold, 0.1-fold, and 0.9-fold of the maximum σ value(σ), as follows:r4=0.2σ r5=0.1   (18)R3=0.9σ  (19)

This inventor have evaluated the CD (critical dimension), through thesimulation of the computer, which is obtained by transferring adownsizing image of pattern of contact holes with various kinds of pitharranged on the reticle plane to the wafer through the projectionoptical system PL, under the distribution of amount of light in whichthe amount of light becomes constant at the five areas comprising thearea 33, and the areas 34A to 34D in FIG. 4 satisfying the condition ofthe equations (18) and (19): becomes 0 at the other areas. In addition,as this simulation, the values of the numerical aperture NA_(PL) of theimage side (wafer side) of the projection optical system PL in FIG. 1A,projection magnification β, and the maximum σ value (σ) are similar tothe equation (12) in the FIG. 3.

The dotted line curve 37 in FIG. 5 shows the simulation result of CDvalue in which the amount of light becomes constant at the five areas ofthis pupil plane, as shown in the curve 37; the CD value is low aroundpitch 500 to 700 nm.

Accordingly, it is understand that the case using the distribution ofamount of light in which the amount of light becomes approximatelyconstant at the nine areas on the pupil plane in FIG. 3 can transfer thepattern across wider pitch range with high resolution than the case ofusing the distribution of amount of light in which the amount of lightbecomes approximately constant at the five areas in FIG. 4.

The Second Embodiment

Nest, the second embodiment according to the present invention will bedescribed accompanying FIG. 10 to FIG. 17. Also in this embodiment, theexposure is fundamentally performed by using the scan exposure typeprojection optical apparatus in FIG. 1A. In this embodiment, however,instead of the diffractive optical element 21 in FIG. 1A, a diffractiveoptical element 22A (described bellow in detail) having differentcharacteristic is used. Accordingly, the diffractive optical element22A, the first prism 71, and the second prism 72 are corresponding to anoptical member for setting a predetermined distribution of amount oflight. In this embodiment, as with the first embodiment, the prism 71,72 (or the first prism 71 only) are used as movable prism.

Further, as shown FIG. 10, it is allow using a pair of prisms 71A, 71Bshaped like a letter V which has diffractive power to one direction andhas not diffractive power to orthogonal direction, as the movable prism.In addition, the prisms 71A, 71B are arranged so that each rectanglearea (in this embodiment, the parallel flat plate) of its center isapproximately orthogonal to the optical axis BX and two slope planes ofthe around area are approximately symmetric with respect to a planebeing orthogonal to the paper of FIG. 1A including the optical axis BX.

With this constitution, by changing the distance between the prisms 71A,71B, positions (distance from the optical axis BX) of a peripheral areain which the amount of light is great concerning above and bellow ofwithin the paper in FIG. 10 (for example, corresponding to X directionin FIG. 12 described bellow in which a distribution of amount of lightof an illumination light at a pupil plane of an illumination system 12)changes.

Next, an illumination system and an illumination method will bedescribed in detail. In this embodiment, a reticle RA is loaded on thereticle stage 14 instead of the reticle R in FIG. 1A.

FIG. 11A shows an example of a pattern (original pattern) fortransferring formed on the reticle RA loaded on the reticle stage 14 inFIG. 1A. In FIG. 11A, a pattern 52 for the one directional high densitypattern is formed, in which square aperture patterns 51 having width ain the X direction and width b in the Y direction, are periodicallyarranged in the X direction (non-scan direction in this embodiment) withpitch P at the pattern region PA. The pitch P is fine pitch (forexample, around 150 nm length converted to projection image on wafer W)which is close to approximate limited resolution of the projectionexposure apparatus in this embodiment, the width a of the X direction isaround ½ of the pitch P, and the width b of the Y direction is aroundequal to the width a to 10-fold (around a to 10a). The pattern 52 is onedirectional high density pattern which can regard an isolated patternabout the Y direction (scan direction in this embodiment). In addition,though the pattern 52 is the periodical pattern arranging four aperturepattern 51 in X direction, the number of the aperture pattern 51 may be2 or any than 2. Further, though the aperture pattern 51 is thetransmission pattern formed in a light shielded film, a light shieldedpattern provided in transmission part may be used instead of it.

Further, another pattern 53 for one directional high density pattern isalso formed at a position distant from the pattern 52 in the Ydirection, in which square aperture patterns 51 with pitch Q larger thanthe pitch P. The pattern 52 and 53 are actually small pattern whoselength of X direction is a few μm or less, various kinds of otherpattern (not shown) may be formed on the pattern region PA of thereticle RA. further, as shown in FIG. 11B, when pattern 52A, 52B, and52C, in which aperture pattern 51 is arranged in the X direction withpitch P respectively, are formed with considerably larger pitch thanpitch P in the Y direction, each of pattern 52A, 52B, and 52C isregarded as one directional high density pattern, can be the target fortransfer in this embodiment. In addition, the plurality of periodicpattern may only be arranged with the distance, so as to be isolated fororthogonal direction (Y direction) to the periodic direction, and theirnumber may be arbitrary.

In order to transfer image of these original patterns on wafer with highaccuracy, as shown FIG. 1A in this embodiment, with arranging thediffractive optical element 22A on the optical path of an illuminationlight IL, the distribution of amount of light (strength distribution) ofthe illumination light IL at the exit plane Q1 (pupil plane) of thefly-eye lens 5 as a predetermined plane.

FIG. 12 shows the distribution of amount of light of the illuminationlight IL at the exit plane Q1 (pupil plane of the illumination system12) of the fly-eye lens 5 in FIG. 1A in this embodiment. In this FIG.12, the direction on the exit plane Q1 corresponding to the X direction(periodically arranging direction) and Y direction (regarding asisolated direction) on the reticle R is respectively defined the Xdirection and Y direction. Here, if the numerical aperture of the objectside (reticle side) of the projection optical system PL in FIG. 1A isNA, the numerical aperture of the image side (wafer side) is NA_(PL), arelation is obtained with using the projection magnification β, asfollows:NA=β·NA _(PL)   (5) (as with the first embodiment)

Further, it is defined that the maximum value among the numericalapertures of the illumination light IL incident to the reticle R fromthe illumination system 12 is NA_(IL), the value of ratio (coherencefactor) of the maximum numerical aperture NA_(IL) to the numericalaperture NA of the projection optical system PL is called maximum σvalue in this embodiment, and maximum σ value is σ_(IL). That is, theillumination light of maximum σ value is the light incident on thereticle R with the maximum angle among the illumination light IL. Themaximum σ value (σ_(IL)) can be expressed, as follows:σ_(IL) =NA _(IL) /NA=NA _(IL)/(β·NA _(PL))   (6A)

In a pupil plane of an illumination system shown in FIG. 12, a maximumouter circle 26 indicates an outer area passed through virtual opticalbeam having the same numerical aperture as the numerical aperture NA atthe incident side of the projection optical system PL, an inner circle27 indicates a circle is tangent to areas passed through illuminationlight having numerical aperture of the maximum σ value (σ_(IL)); allillumination light pass though within the circle 27. The radius σ of thecircle 27 is equal to σ_(IL)·NA, as follows:σ=NA _(IL)=σ_(IL) ·NA=σ _(IL) ·β·NA _(PL)   (6B)

Further, in FIG. 12, the origin point of the X axis and Y axis is on theoptical axis BX. The illumination light IL, in FIG. 12, has thedistribution of amount of light with the approximate constant amount oflight at the three areas (hatched areas) including the annular zone area54 with the radius r4 which centers on the optical axis BX of theillumination system 12 and the two circular areas 55A, 55B with theradius r5 sandwiching the area 54 in the X direction; and with thesmaller amount of light (approximate 0 in this embodiment) than theconstant amount of light. That is, the centers of the three areas 54,55A, and 55B are arranged along the straight line which passes throughthe optical axis of the illumination system and parallels the X axis(periodically arranging direction of one directional high densitypattern as target for transfer), the distance between the each center ofthe area 55A and 55B both ends and the optical axis BX is respectivelyR3.

Further, the annular zone area 54 has ½ annular in which the innerradius is ½ of the outer radius r4, ⅓ annular in which the inner radiusis ⅓ of the outer radius r4, or ⅔ annular in which the inner radius is ⅔of the outer radius r4 and the like. In addition, as shown FIG. 15A, thecircular area 54A with the radius r4 can be used instead of the annularzone area 54. Further, a plurality of areas substantially split can beused instead of the annular zone area 54. Concretely, as shown in FIG.15C, the distribution of amount of light at the two half-circular (orcircular etc.) areas 54A1, 54A2 split in the Y direction (or Xdirection), in which the amount of light become great, may be usedinstead of the annular zone area 54. In this case, the amount of lightmay become great at a four-way split area in the X direction and Ydirection (or direction crossed these axes) instead of the annular zonearea 54. Furthermore, distribution in which the amount of lightgradually decreases toward outer may be near the outline of the area 54,55A, 55B. The center area 54 is corresponding to the first area, and thetwo areas 54A and 54B sandwiching it is respectively corresponding tothe second area and third area. Hereinafter, the radii r4, r5 and R3respectively indicate the radius σ in the equation (6B) (distancebetween point passed through the optical beam of the maximum σ value andthe optical axis BX) corresponding to the maximum σ value (σ_(IL)) asunit.

In this embodiment, the radii r4, r5 are preferably set within around0.1σ to 0.2σ respectively, as follows:0.1σ≦r4≦0.2σ  (21)0.1σ≦r5≦0.2σ  (22)

If the values of the radii r4, r5 are smaller than the lower limit ofthe equation (21), equation (22), the depth of focus of the projectionoptical system PL becomes shallow for the optical beam in the isolateddirection of one directional high density pattern; if the values of theradii r4, r5 are greater than the upper limit of the equation (21),equation (22), the depth of focus of the projection optical system PLbecomes shallow for the optical beam in the periodic direction of onedirectional high density pattern (described bellow in detail).Furthermore, radius r4 and radius r5 are preferably equal, as follows:r4≈r5   (23)

Further, the areas 55A and 55B of each end in FIG. 12 are inscribed tothe circle 27 of the maximum σ value. Accordingly, the equation holds,as follows:R3=σ−r5   (24)

In this case, the diffractive characteristic of the diffractive opticalelement 21 in FIG. 1A is set, so as to obtain the distribution of amountof light in which the amount of light approximately becomes constant atthe area 54, the areas 55A, 55B in FIG. 12 satisfying the condition ofthe equations (21) to (24); approximately becomes 0 at other areas. Forthe reason, the diffractive optical element 22A, as an example, canfabricate by forming a concave and convex grating having approximatelysystematically along in the direction of the straight line 31A, and aconcave and convex grating having approximately systematically along theX axis of FIG. 12. Alternatively, the diffractive optical element 22Amay be a combination of a plurality of phase type diffractive gratings.In these cases, since the diffractive optical element 22A is phase type,it is advantage of high efficiency for using light. In addition, it isable to use an optical element changing refractive index distributioncorresponding to a diffractive grating distribution as an opticalelement 22A. In addition, a construction and a method for fabricatinghaving a specific diffractive characteristic is closely disclosed, forexample, in Japanese Patent Application Laid-open No. 2001-176766(corresponding to U.S. Pat. No. 6,563,567) by this applicant.

In addition, it is allowed that the amount of light distributionobtained by diffraction optical device 22A is set to be approximatelythe predetermined of light at a region including regions 54, 55A and 55Bin FIG. 12. Furthermore then, an aperture stop where an aperture isformed at a portion corresponding to the regions 54, 55A and 55B in FIG.12 may be disposed on the emission plane Q1 (pupil plane) of the fly eyelens 5 in FIG. 1A. Also in this case, advantage in which utilizationefficiency of the illumination light IL is high is obtained.

There will be explained, while referring to FIG. 13, the focus lightflux, when illuminating the pattern 52 of the one directional highdensity contact hole (one directional high density pattern) of reticleRA in FIG. 11A with the amount of light distribution of the illuminationlight in FIG. 12.

FIG. 13A shows diffraction light (focus light flux) diffracted in theisolated Y direction from the pattern 52. FIG. 13B shows diffractionlight (focus light flux) diffracted in the periodic X direction from thepattern 52. In FIGS. 13A and 13B, light beams 58, 59 and 60 show theillumination light IL passed through the regions 54, 55A and 55B on thepupil plane of the illumination system in FIG. 12 respectively. Thediffraction light generated from the pattern 52 (aperture pattern 51)due to the light beams 58, 59 and 60 generates, in the Y direction, withdistribution in which the diffraction light is generated most stronglyat the center, and the larger the tilt angle, the lower the intensitydecreases, as shown in FIG. 13A.

On the other hand, as shown in FIG. 13B, there are positive primarylight 58P and negative primary light 58M in addition to zero-orderlight, in the diffraction light generated in the X direction from thepattern 52 by illumination of the light beam 58 from the region 54 withoptical axis BX in FIG. 12 as center. At this point, the pattern 52 isresolution limit, therefore, the positive primary light 58P and thenegative primary light 58M can not be passed through the projectionoptical system PL in FIG. 1. Further, the zero-order light generated inthe X direction from the pattern 52 by the illumination of the lightbeams 59 and 60 from the regions 55A and 55B of both ends in FIG. 12 istaken to as the zero-order lights 59 and 60 respectively, as shown inFIGS. 13A and 13B. The pattern 52 of this embodiment is approximatelythe resolution limit, therefore, the positive primary light 59P from thepattern 52 due to one light beam 59 is made incident into the projectionoptical system PL in FIG. 1A in parallel to the other zero-order light60, while, the negative primary light 60M from the pattern 52 due to theother light beam 60 is made incident into the projection optical systemPL in FIG. 1A in parallel to one zero-order light 59.

Further, wavelengths of incident light beams 58, 59 and 60 are taken toas λ, exit angle in the X direction to the normal line of the pattern 52of the zero-order light 59 is taken to as θ, and exit angle in the Xdirection to the normal line of the pattern 52 of the zero-order light60 is taken to as −θ, and in FIG. 13B, among the other light beams 59,the light beam passed through the adjacent aperture pattern 51 withinterval P of the X direction is taken to as the light beams 59A and59B. In this case, differential value ΔA of the optical path lengthbetween the positive primary light 59AP of the light beam 59A and thepositive primary light 59BP of the light beam 59B equals to thewavelength λ as follows:ΔA=2·P·sin θ=λ  (25)

Furthermore, the interval R3 in the X direction between the regions 55Aand 55B, and the optical axis BX in FIG. 12 corresponds to sin θ of theexit angle θ of the zero-order light of the light beams 59 and 60 inFIG. 13B as follows:R3=σ−r5=sin θ  (26)

In addition, equation (26) corresponds to the case in which focaldistance fQ1 at the side of the emission plane Q1 of the partial opticalsystem between the emission plane Q1 (pupil plane) in the illuminationsystem 12 in FIG. 1A and the reticle plane is set to 1. Nextrelationship is approved from the equations (25) and (26). Since, thereis no unit of the interval R3 of the equation (26), unit of both sidesof next equation becomes length.P=λ/(2·R3)=λ/{2(σ−r5)}  (27A)

In other words, equation (27A) indicates resolution limit of X direction(cycle direction) in the object plane (reticle plane) of the projectionexposure apparatus of this embodiment, in which the larger is theinterval R3 while making σ larger or while making radius r5 smaller, theless it is possible to make the pitch P to be the resolution limitsmaller. The pitch P is converted into pitch β·P as the followingequation, which the pitch β·P is length on the wafer. The pitch β·Pbecomes the resolution limit in the X direction on the image plane(wafer plane) of the projection optical system PL.β·P=β·λ/{2(σ−r5)}  (27B)

In this embodiment, the wavelength λ is set to 193.306 nm. As oneexample, numerical aperture NA_(PL) at the wafer side of the projectionoptical system PL is taken to be 0.85, projection scale factor β of theprojection optical system PL is taken to be ¼, σIL to be σ value ofillumination system 12 is taken to be 0.90, and radius r5 of the regions55A and 55B in FIG. 12 is taken to be 0.14σ, that is called as “thefirst illumination condition”. The resolution limit β·P at the imageplane side under this condition becomes about 147 nm as shown in nextequation from relationship of the equations (6B) and (27B).β·P=146.7 (nm)   (28)

FIG. 12 can be regarded as the drawing showing amount of lightdistribution in the X direction in the pupil plane Q3 of the projectionoptical system PL in FIG. 1A. In this case, the regions 54, 55A and 55Bin FIG. 12 correspond to position through which the zero-order light ofthe illumination light IL is passed, and the positive primary light inthe X direction of the illumination light IL according to the pattern 52in FIG. 11A becomes distribution in which the amount of lightdistribution in the circumference 27 is moved in parallel toward theregion in the circumference 57A with the spaced point 56A as the center,which the spaced point 56A is spaced from the optical axis BX (opticalaxis AX of the projection optical system PL) by only interval 2·R3 inthe +X direction. Similarly, the negative primary light in the Xdirection of the illumination light IL according to the pattern 52becomes distribution in which the amount of light distribution in thecircumference 27 is moved in parallel toward the region in thecircumference 57B with the spaced point 56A as the center, which thespaced point 56B is spaced from the optical axis BX (optical axis AX) byonly interval 2·R3 in the −X direction. In this case, the positiveprimary light (or the negative primary light) of the light beam passingthrough the region 55B (or 55A) passes through the region 55A (or 55B),therefore, the image of the pattern 52 is projected on the wafer withhigh resolution.

In addition, if a part of the positive primary light (negative primarylight) of the light beam passing through the region 55B (55A) is passedthrough within the circumference 26, the image of the pattern 52 isimaged, therefore, actual resolution limit β·P at the image plane sidebecomes smaller value than that of the equation (28).

Concerning this embodiment, the present inventor, in order to obtain theoptimum balance between radius r4 of central region 54 and radius r5 ofthe regions 55A and 55B at both ends in FIG. 12, has calculated depth offocus (DOF) of the image according to the projection optical system PLwith simulation of the computer while varying the radius r4 gradually.The condition in addition to the r4, at this time, is the same as theabove described first illumination condition, and the radius r5 is0.14σ. Furthermore, the pitch P of the pattern 52, in FIG. 11A, is takento be 145 nm to be approximate resolution limit, and the width a in theX direction of the aperture pattern 51 is taken to be 70 nm, and width bin the Y direction is taken to as 500 nm. It should be noted that thepitch P, and the widths a and b are lengths which are converted on theimage plane of the projection optical system PL respectively.

The curved line 61 in FIG. 14 shows the simulation results, and thehorizontal axis in FIG. 14 is the radius r4 (unit is σ) of the region 54(center σ) of the center of FIG. 12, and the vertical axis iscalculation results of the depth of focus (DOF) (nm) corresponding tothe value of the radius r4. As known from the curved line 61, there isobtained the depth of focus more than approximate 100 nm within therange in which the radius r4 is from 0.1σ to 0.2σ. In addition, when theradius r4 is σ1 (=0.14σ), that is, when the radius r4=r5 isapproximately approved, there is obtained the deepest depth of focus. Inthis case, even though some degree of unevenness exist on the wafer as asubstrate, curvature and the like occur on the image plane within theabove described exposure region by aberration of the projection opticalsystem PL or the like, or certain degree of tracking error of the focusposition remains at the time of exposure in the scanning exposuremethod, for instance, it is possible to transfer the one directionalhigh density pattern with high resolution. It should be noted that whenthe radius r4 becomes smaller than degree of 0.1σ, the depth of focus ofthe focus light flux in the isolated direction of the pattern 52 in FIG.11A becomes narrow. On the other hand, when the radius r4 becomes largerthan degree of 0.2σ, the depth of focus of the focus light flux in thecyclic direction of the pattern 52 in FIG. 11A becomes narrow, by theflare effect of the light beam from the region 54 of the center of FIG.12.

In addition, in the pattern 53 of the one directional high densitycontact hole existing in the position spaced from the pattern 52 of FIG.11A, arrangement direction is the same as that of the pattern 52, andthe pitch Q is larger than the pitch P, therefore, the pattern 53 istransferred on the wafer with high resolution under the above describedillumination condition.

As described above, by employing the amount of light distribution on thepupil plane of this embodiment in FIG. 12, the pattern of the reticle RAincluding the pattern 52 of the one directional high density contacthole of FIG. 11A is capable of being transferred on the wafer W in the Xdirection and the Y direction with high resolution.

In addition, for instance, when one directional high density patternwith X direction as cyclic direction and one directional high densitypattern with Y direction as cyclic direction are formed on the reticleRA of FIG. 11A, it is allowed that arrangement direction of threeregions 54, 55A 55B through which the illumination light of FIG. 12 ispassed in parallel to the cyclic direction of the pattern which has thesmallest pitch among them. At this time, three regions 54, 55A and 55Bare allowed to be disposed on the straight line in parallel to thecyclic direction of one pattern which is passed through the optical axisBX on the pupil plane of the illumination system 12 and whose pitch isthe smallest one. At least one of 2 regions 55A and 55B except for thecentral region 54 is allowed that distance of the optical axis BXconcerning the direction in parallel to the cyclic direction of theother pattern is not zero, or the distance is allowed to be set inaccordance with the pitch of the other pattern, for instance.

Furthermore, numerical aperture NA_(PL) at the image side of theprojection optical system PL, the projection scale factor β, and themaximum σ value (σ_(IL)) of the illumination system 12 are capable oftaking arbitrary value without restricting the value to the abovedescribed values. For instance, position (distance of the optical axisBX concerning X direction to the region 55B) in the radius direction ofthe regions 55A and 55B where peripheral amount of light is large amongamount of light distribution of FIG. 12 is allowed to be varied whilevarying interval between prisms 71 and 72 of FIG. 1A to control themaximum σ value (σ_(IL)), or the interval R3 of FIG. 12. It is possibleto control the maximum σ value similarly, also by employing the V-typeprisms 71A and 72A of FIG. 10 instead of the prisms 71 and 72.

In addition, in the amount of light distribution of FIG. 12, it isallowed that the amount of light (for instance, intensity per unit area)of the center region 54 is made different from the amount of light ofperipheral 2 regions 55A and 55B. Relative largeness of these lightquantities is allowed to be adjusted so that the optimum resolution canbe obtained every transferring pattern, for instance. Furthermore, inthis embodiment, it is allowed that distributed light in peripheralregions 55A and 55B of FIG. 12 may be made linearly polarized light. Atthis occasion, it is allowed that, as one example, the light distributedon the peripheral regions 55A and 55B is made S polarization in whichthe polarizing direction is direction of the tangential line (verticaldirection to incident plane). By this matter, in some cases, resolutionand so forth to the specific pattern are improved.

In addition, when the lights which are respectively distributed at threeregions having large peripheral amount of light described above whilebeing generated from the light source 1 are non-polarized lights, or thepolarizing direction thereof do not agree with the direction of thetangential line, it is preferable that the lights are converted into thelight beam of the linear polarized light in which the polarizingdirection approximately agrees with the direction of the tangential lineupon disposing the polarization setting member such as a half-wave plateor a quarter-wave plate or so forth on the optical path through whichthe lights distributed at respective regions are passed between thediffraction optical device 21 (polarizing member) and the fly eye lens5, for instance. At this time, it is preferable that there is providedthe polarization setting member at incident side of one prism (movablemember) which is movable along the optical axis BX and disposed at themost upstream (light source side) between one pair of the prismsdescribed above, for instance, between the movable member and the lens4, or between the diffraction optical device described above and thelens 4. In this case, it is not necessary to move the polarizationsetting member in accordance with variation of direction of travel ofthe light beam (optical path) caused by exchange of the diffractionoptical device or interval change of one pair of prisms or so forth, orit is not necessary to form the polarization setting member largely inanticipation of its variation.

In addition, the diffraction optical device 22A in this embodiment setsthe amount of light distribution on the pupil plane of the illuminationsystem 12 as the predetermined plane into predetermined condition,however, the predetermined plane is possible to be the pupil plane Q3 ofthe projection optical system PL of FIG. 1A. At this time, in the casethat the reticle RA does not exist caused by its diffraction opticaldevice 22A, the amount of light distribution, which becomesapproximately constant in the first region including the optical axis AXand in two regions putting the first region therebetween, and becomeslower amount of light than it at the region in addition thereto, is setin the pupil plane Q3 of the projection optical system PL.

In addition, in this embodiment, the regions 54, 55A and 55B, which haveapproximately constant amount of light on the pupil plane, have circularform (or annular form), however, outward form of those regions arepossible to be respective oval regions. Further, outward form of eachregion is possible to be rectangular region as described later,furthermore, outward form of each region is possible to be combinedbetween the circular (or oval) region and the rectangular region.

FIG. 15B shows another possible amount of light distribution on itspupil plane, as shown in FIG. 15B, the amount of light distributionbecomes approximately the predetermined of light at the frame shapedregion 54B of the center rectangular shape (regular hexagon or so forthis possible in addition to square), and at two rectangular regions 55Cand 55D, which put the region 54B therebetween in the X direction, andthe amount of light distribution becomes low at the region in additionthereto. In this case, position and area of the rectangular (or frameshape) region are allowed to be approximately the same as the positionand area of the regions 54, 55A and 55B of FIG. 12.

Next, from the above described equations (27A) or (27B) in the amount oflight distribution of the illumination light on the pupil plane of FIG.12, it is seen that the larger is σ to be radius of the circumference 27and the smaller is the radius r5 of the regions 55A and 55B at bothends, the smaller it is possible to minimize the resolution limit P (orβP). However, when the radius r5 becomes smaller than degree of 0.1σ,the depth of focus becomes shallow. Consequently, there will beexplained the method capable of improving the resolution whileminimizing the radius r5 substantially and maintaining the depth offocus deep below. For that reason, there is provided the seconddiffraction optical device 22B having slightly different diffractionproperty in the revolver 24 of FIG. 1A. When the second diffractionoptical device 22B is mounted on the optical path of the illuminationlight IL, there is obtained the amount of light distribution, whichbecomes approximately the predetermined of light at three regions 62,63A and 63B of FIG. 16A, and becomes the amount of light lower than it(approximate zero in this embodiment) in the region in addition thereto,at the emission plane Q1 (pupil plane) of the fly eye lens 5.

FIG. 16A shows the amount of light distribution of the illuminationlight IL in the emission plane Q1 (the pupil plane of the illuminationsystem 12) of the fly eye lens 5 in FIG. 1A in the case that the seconddiffraction optical device 22B is used. In FIG. 16A where the same signis added to corresponding part to FIG. 12, there is set two oval regions63A and 63B (the second region and the third region) having the shape inwhich slender in the Y direction is external form, width in the Xdirection is t, and length in the Y direction is h (h>t), so as to putthe circular region 62 (the first region) of the radius r6 between thesetwo oval regions 63A and 63B in the X direction, with the optical axisBX of the illumination system 12 in FIG. 1A as the center, so that theinterval from the optical axis BX to each center becomes R4. Also inthis example, the center region 62 is allowed to be the annular shape.Two slender oval regions 63A and 63B are the overlapped region in whichthe region in the circumference 27 having the radius σ is overlapped bythe region in the circumferences 65A and 65B whose radii are NA (or σ ispossible) by employing the positions 64A and 64B, which have theinterval of R5 from the optical axis BX, as the center. On thisoccasion, the interval R4 is set longer than the interval R3 from theoptical axis BX in FIG. 12 to the center of the regions 55A and 55B, theintervals R4 and R5 are capable of being expressed with the followingequations.R4=(σ−t/2)>R3   (29A)R5=R4+NA−t/2   (29B)

In order to bring the relation of R4>R3 into existence, on theassumption that the equation (22) is already brought into existence, ½of the width t in the X direction of oval regions 63A and 63B, as oneexample, is set approximately to next range. Similarly, the radius r6 ofthe center circular region 62 is set within the range of approximatelythe degree of two times of t/2.0.025σ≦t/2≦0.075σ  (30)0.05σ≦r6≦0.16σ  (31)

More desirably, t/2 is set to the degree of 0.05σ. The resolution limitP in the X direction on the object plane of the corresponding projectionoptical system PL to the equation (27A) in these cases becomes smallerthan the value of the equation (27A) as the following equation.P=λ/(2·R4)<λ/(2·R3)   (32)

Also, concerning the illumination condition in FIG. 16A, the presentinventor, in order to obtain the optimum balance between radius r6 ofcentral region 62 and half width (t/2) of the oval regions 63A and 63Bat both ends, has calculated depth of focus (DOF) of the image accordingto the projection optical system PL by simulation of the computer whilevarying the radius r6 gradually. In the illumination condition (thesecond illumination condition) on this occasion, the wavelength λ is setto 193.306 nm. Numerical aperture NA_(PL) at the wafer side of theprojection optical system PL is taken to be 0.85, projection scalefactor β is taken to be ¼, σIL to be σ value of illumination system 12is taken to be 0.93, and the half width (t/2) of the oval regions 63Aand 63B is taken to be 0.05σ. In addition, the pitch P of the pattern52, in FIG. 11A of the object of transfer is taken to be 140 nm to beapproximately resolution limit, and the width a in the X direction ofthe aperture pattern 51 is taken to be 70 nm. It should be noted thatthe pitch P, and the widths a and b are lengths which are converted onthe image plane of the projection optical system PL respectively.

The curved line 66 in FIG. 17 shows the simulation results, and thehorizontal axis in FIG. 17 is the radius r6 (unit is σ) of the region 62(center σ) of the center of FIG. 16A, and the vertical axis iscalculation results of the depth of focus (DOF) (nm) corresponding tothe value of the radius r6. As known from the curved line 66, there isobtained the depth of focus more than approximate 250 nm within therange in which the radius r6 is from degree of 0.05σ to 0.16σ. Inaddition, when the radius r6 is σ2 (=0.11σ), that is, when the radiusr6=t is approximately brought into existence, there is obtained thedeepest depth of focus (about 350 nm). Accordingly, by employing theillumination condition in FIG. 16A, there is obtained higher resolutionto the one directional high density pattern, and the deep depth offocus. In this embodiment, even though the width in the X direction(cycle direction) of the regions 63A and 63B of both ends in FIG. 16Abecomes narrow, the areas of the regions 63A and 63B are approximatelythe same degree as the areas of the regions 55A and 55B in FIG. 12,therefore, the deep depth of focus can be obtained.

In addition, instead of the center circular region 62 in FIG. 16A, asshown in FIG. 16B, it is also allowed that there may be used the amountof light distribution where the amount of light becomes large at theoval region 62A with X direction as longitudinal direction, in which Xdirection is direction (that is, direction in parallel to arrangementdirection of three regions) perpendicular to the longitudinal directionof the peripheral oval regions 63A and 63B. In the amount of lightdistribution in FIG. 16B, the amount of light of two oval regions 63Aand 63B, which put the oval region 62A therebetween, becomes large.Thus, by making the central region 62 oval shape, in some cases, it ispossible to improve resolution in the isolated direction with respect tothe one directional high density pattern without reducing the amount oflight.

In addition, in the amount of light distribution of FIGS. 16A and 16B,it is allowed that the amount of light (for instance, intensity per unitarea) of the center regions 62 and 62A is made different from the amountof light of peripheral regions 63A and 63B.

Furthermore, it is also allowed that distributed light in peripheralregions 63A and 63B in FIGS. 16A and 16B may be made linearly polarizedlight (for instance, longitudinal direction is the polarizingdirection). In particular, in the amount of light distribution in FIG.16B, as one example, it is preferable that the light distributed at theperipheral oval regions 63A and 63B is made the linear polarized light(S polarized light) in which the polarizing direction is thelongitudinal direction thereof as shown by the arrows PC and PB (thatis, the longitudinal direction is the direction corresponding toisolated direction of the pattern of the reticle in FIG. 11A). In thisoccasion, furthermore, it is preferable that the light distributed atthe center oval region 62A is made the linear polarized light in whichthe polarizing direction is the longitudinal direction thereof (that is,the longitudinal direction is the direction corresponding to the cycledirection of pattern of the reticle in FIG. 11A) as shown in the arrowPA. By this matter, in some cases, resolution and so forth to thespecific pattern are improved.

In addition, when the lights distributed at the peripheral regions 63Aand 63B are non-polarized lights, or the polarizing direction thereof donot agree with the longitudinal direction of the tangential line, in theamount of light distribution in FIGS. 16A and 16B, like the above, forinstance, it is preferable that the polarization setting member isprovided between the diffraction optical device and the fly eye lens 5.Similarly, in the amount of light distribution in FIG. 16B, when thelights distributed at the center region 62A are the non polarizedlights, or the polarizing direction thereof does not agree with thelongitudinal direction, it is preferable that its polarized condition isadjusted by the above polarization setting member.

Third Embodiment

Next, there will be explained a third embodiment of the presentinvention referring to FIG. 18 to FIG. 21. The first embodiment usesmember including the diffraction optical devices 21, 22 as the opticalmember for setting the predetermined amount of light distribution, onthe contrary, this embodiment uses the aperture stop as the opticalmember thereof, and in FIG. 18, there is attached the same symbol to aportion corresponding to FIG. 1A to omit its detailed description.

FIG. 18 shows a configuration of the projection exposure apparatus ofthis embodiment, in this FIG. 18, the illumination light IL from theexposure light source 1, is made incident into the fly-eye lens 5 viathe beam expander 2 and the mirror 3. There is disposed the aperturestop (σ stop) 42 as the optical member for obtaining the predeterminedamount of light distribution at the emission plane Q1 as thepredetermined plane, in the emission plane Q1 (the pupil plane of theillumination system 12) of the fly-eye lens 5 of this embodiment. Theaperture stop 42 is mounted on the revolver 41, and the revolver 41 ismounted with another aperture stop 44, and further, still anotheraperture stop (not shown in the drawings). The present embodiment is soconstituted that the illumination condition is capable of being switchedupon providing either of the aperture stops 42, 44 and so forth at theemission plane Q1 (pupil plane) while controlling the rotation angle ofthe revolver 41 via the driver 43 by the main control system 17.

The illumination light IL passed through the aperture stop 42illuminates a slender illumination region of the pattern plane (reticleplane) of the reticle R as the mask with uniform intensity distributionvia the condenser lens system 6, the field stops 7, 8, the image-forminglens system 9, the mirror 10 and the main condenser lens system 11. Theillumination system 12 of the present embodiment is constituted by theexposure light source 1, the beam expander 2, the mirror 3, the fly-eyelens 5, the aperture stop 42 (or another aperture stop), the condenserlens system 6, the field stops 7, 8, the image-forming lens system 9,the mirror 10 and the main condenser lens system 11. The constitution inaddition to the above is the same as the embodiment in FIG. 1A.

In this embodiment, the pattern on the reticle R of the object oftransfer is the pattern including the contact hole having three-kind ofdifferent pitches as shown in FIG. 2. The aperture stop 42 in FIG. 18,in accordance with this, forms nine apertures in the shading plate toobtain the same amount of light distribution as the amount of lightdistribution in FIG. 3.

FIG. 19 shows the shape of the aperture stop 42. In FIG. 19, in theaperture stop 42 comprised of the shading plate, the aperture stop 42 isformed with nine apertures each of which is spaced mutually, whichinclude a circular shaped aperture 45 with the optical axis BX of theillumination system 12 as the center, four circular shaped apertures46A, 46B, 46C and 46D in which respective centers are disposed along thefirst circumference surrounding the aperture 45, and four circularshaped apertures 47A, 47B, 47C and 47D in which the centers thereof aredisposed along the second circumference surrounding the apertures 46A to46D. In addition, positions and shapes of the aperture 45, apertures 46Ato 46D, and apertures 47A to 47D are the same as that of the region 28,region 29A to 29D, and regions 30A to 30D in which amount of light isapproximately constant on the respective amount of light distribution inFIG. 3.

Accordingly, by employing the aperture stop 42, the amount of lightdistribution on the emission plane Q1 (pupil plane) of the fly-eye lens5 becomes approximately constant at nine regions shown in FIG. 3 likethe first embodiment, and becomes low at the region in addition thereto,therefore, it is possible to transfer the reticle pattern imageincluding the contact hole having various kind of pitch as FIG. 2 on thewafer at once with high resolution. In the case that the aperture stop42 is used as this embodiment, the utilization efficiency of theillumination light IL decreases, however, there is advantage that it ispossible to set the amount of light distribution at the predeterminedplane (the pupil plane or so forth of the illumination system 12) intothe required condition accurately using simple constitution.

In addition, it is also allowed to use an aperture stop (also numbered42) in which the center aperture is made the annular aperture 45R asshown in FIG. 20, instead of the aperture stop 42 in FIG. 19, or bycombining it. In this case, the amount of light distribution, which isthe same as FIG. 6A, is obtained accurately and easily, therefore, it ispossible to further improve the resolution or the depth of focus. Inaddition, it is possible to form the amount of light distribution, whichis the same as that of FIG. 6B, upon coupling two apertures respectivelylined up in the radius direction at the aperture stop 42 in FIG. 20.

Further, the aperture stop 44 in FIG. 18, as shown in FIG. 21, is thestop in which the annular region 33R in FIG. 7A and corresponding partsto the regions 34A to 34D are made the bracelet shaped aperture 48R andthe circular shaped apertures 49A to 49D respectively. Accordingly, byinstalling the aperture stop 44 on the emission plane Q1 (pupil plane)of the fly-eye lens 5, the amount of light distribution on the pupilplane, like FIG. 7A, becomes approximately constant at five regions, andbecomes approximately zero at the region in addition thereto, therefore,there is obtained the wide depth of focus and high resolution withrespect to the patterns having various kind of pitches.

In addition, it is possible to form the amount of light distribution,which is the same as that in FIG. 7B, upon coupling the annular shapedaperture 48R to the circular apertures 49A to 49D in the aperture stop44 in FIG. 21.

In addition, in the present embodiment, a part other than the apertureis taken to as the light shielding part in the aperture stops 42, 44,however, it is also allowed that a part other than the aperture is takento as a light attenuating part (a part where the light transmittance issmall). In this case, in the amount of light distribution on the pupilplane of the illumination system, like FIG. 3, FIG. 6A and FIG. 7A, theamount of light does not become zero in the region other than fiveregions or nine regions. Further, in the present embodiment, theaperture stop is disposed on the pupil plane or the conjugated planethereof of the illumination system 12, however, it is allowed that theaperture stop is disposed on a part adjacent to the incident plane ofthe fly-eye lens 5, for instance.

Fourth Embodiment

Next, referring to FIG. 22, a fourth embodiment of the present inventionwill be explained. The second embodiment employs the member includingthe diffractive optical elements 22A and 22B as the optical member forsetting a predetermined distribution of amount of light, whereas thisembodiment employs the aperture stop as its optical member. For this, inthis embodiment, similarly to the third embodiment, the scan exposuretype of the projection exposure apparatus of FIG. 18 is employed forexposure. However, in this embodiment, aperture stops 42A and 42B to belater described are used instead of the aperture stops 42 and 44 of FIG.18 respectively, and the reticle stage RA of FIG. 1A is loaded onto thereticle stage 14 instead of the reticle R.

Also in this embodiment, it is assumed that the pattern of the reticleRA, being an object of transfer, is a pattern 52 including the patternof one directional high density contact hole that is arranged in a pitchP in the X direction shown in FIG. 11A. In response hereto, the aperturestop 42A of FIG. 18 is produced by forming three apertures in theshading plate in order to obtain the distribution of amount of lightidentical to that of FIG. 12.

FIG. 22A shows a shape of its aperture stop 42A and in FIG. 22A, theaperture stops 42A to be composed of the shading plate has the threeapertures including an annular aperture 66 with the optical axis BX ofthe illumination system 12 of FIG. 18 centered, and two circularapertures arranged so as to hold its aperture 66 between them, each ofwhich is spaced from each other. In addition, the position and shape ofthe apertures 66, 67A and 67B are identical to areas 54, 55A and 55Bhaving approximately constant amount of light on the distribution ofamount of light of FIG. 12 respectively.

Accordingly, by employing the aperture stop 42, the distribution ofamount of light on the exit plane Q1 (pupil plane) of the fly-eye lens 5becomes approximately constant in three areas shown in FIG. 12 similarlyto the second embodiment, and it becomes low in the area other than it,whereby the image of the pattern of the reticle including the pattern 52of the one directional high density contact hole can be transferred ontothe wafer with a high resolution in the X direction and the Y direction.In a case of employing the aperture stop 42A like the case of thisembodiment, the utilization efficiency of the illumination light IL islowered; however there exists an advantage that the simple configurationenables the distribution of amount of light on a predetermined plane(the pupil plane of the illumination system 12 or its conjugate plane)to be accurately set in a desired state.

In addition, the second aperture stop 42B of FIG. 18, as shown in FIG.22B, is an aperture stop having the aperture 68 and slender ovalapertures 69A and 69B formed responding to the circular area 62 and theslender oval areas 63A and 63B of FIG. 16A respectively. Accordingly,installing the aperture stop 42B on the exit plane Q1 (pupil plane) ofthe fly-eye lens 5 of FIG. 18 enables the pattern of the one directionalhigh density contact hole to be transferred onto the wafer with a highresolution and yet at a deep depth of focus, similarly to the case ofemploying the illumination condition of FIG. 16A. In addition, in thisembodiment, not only the aperture stops 42A and 42B shown in FIG. 22Aand FIG. 22B, but also, for example, the aperture stop forming thedistribution of amount of light shown in FIG. 15A to FIG. 15C and FIG.16B can be used.

Additionally, in this embodiment, the aperture stop may be arranged notonly on the pupil plane of the illumination system 12 or its conjugateplane, but also arranged closely to the incident plane of, for example,the fly-eye lens 5. In addition, in this embodiment, the section otherthan each of the aperture stops 42A and 42B is assumed to be a shadingsection; however the section other than its aperture may be assumed tobe a light-reducing section (the portion having less quantity of light).In this case, with the distribution of amount of light on the pupilplane of the illumination optical-system 12, the amount of quantity doesnot become zero on the area other than three areas.

Fifth Embodiment

Next, referring to FIG. 23, a fifth embodiment of the present inventionwill be explained. The above-mentioned first to fourth embodimentsemploy the fly-eye lens as an optical integrator (uniformizer orhomogenizer), whereas this embodiment uses an inner-plane reflectiontype integrator, for example, a rod type integrator as the opticalintegrator.

FIG. 23 shows the main part of the illumination system of the projectionexposure apparatus of this embodiment, and this optical system of FIG.23 is arranged, for example, between the mirror 3 of the illuminationsystem 12 and the fixed field stop 7 of FIG. 1A. In FIG. 23, theillumination light IL from the exposure light source, which is not shownin the figure, enters the diffractive optical element 21 having anidentical configuration to that of the first embodiment or thediffractive optical element 22A having an identical configuration tothat of the second embodiment. The diffracted light from the diffractiveoptical element 21 (or 22A) is gathered in nine (or three) areas on theplane Q4 as a predetermined plane via a relay lens 152. In addition, theillumination light that has passed through the plane Q4 is gathered inthe incident plane of a rod integrator 151 via a condenser lens 153. Inthis case, the plane Q4 is approximately positioned at the frontal focusplane of the condenser lens 153, and the incident plane of the rodintegrator 151 is approximately positioned at the rear focus of thecondenser lens 153.

In addition, the exit plane Q5 of the rod integrator 151 is a conjugateplane with the reticle plane, the fixed field stop 154 is arranged inthe vicinity of this exit plane Q5, and closely hereto a movable fieldstop (not show in the figure) is arranged. In addition hereto, theillumination light to be injected from the rod integrator 151illuminates a pattern of the reticle, which is not shown in the figure,through the optical system similar to the imaging lens system 9 and themain condenser lens system 11.

Also, in this embodiment, the distribution of amount of light shown inFIG. 3 (or FIG. 12) on the plane Q4 is set by using the diffractiveoptical element 21 (or 22A), thereby enabling the image of the pattern(or pattern including the one directional high density contact hole)including the variously pitched contact holes to be transferred onto thewafer at a time and with a high precision.

In addition, also in this embodiment, instead of employing thediffractive optical element 21, the aperture stop provided with nineapertures similar to the aperture stop 42 of FIG. 19 and FIG. 20, or theaperture stop 44 of FIG. 21 may be arranged on the plane Q4. Further, asdescribed above, also in this embodiment, when it is necessary to adjustthe deflection state of the luminous flux in at least one out of aplurality of the areas, for example, nine, five, or three areas, inwhich the amount of light is enhanced with the distribution of amount oflight on the pupil plane of the illumination system, for example, theforegoing deflection setting member may be installed on the plane Q4.

Further, in FIG. 23, the diffractive optical element 22B of FIG. 1A forsetting the distribution of amount of light of FIG. 16A may be arrangedinstead of the diffractive optical element 22A. In addition, asdescribed above, when it is necessary to adjust the deflection state ofthe luminous flux in at least one out of three areas, in which theamount of light is enhanced with the distribution of amount of light onthe pupil plane of the illumination system, for example, the foregoingdeflection setting member may be installed on the plane Q4.

In addition, one pair of the interval-variable prisms 71 and 72 (movableprisms) of FIG. 1A may arranged for example, between a lens 152 of FIG.23 and the plane Q4 to make the position in the radial direction of thearea, in which the amount of light of the vicinity is large, variable.

Additionally, as the rod integrator 151 can be used thelight-transmissive optical member that is of polygonal column shape, forexample, of square column shape, of hexagonal column shape, etc. or thereflective member of such hollow metal etc. that is of polygonal columnshape or of cylindrical column shape as mentioned above.

In addition, the focus point of the illumination light lL (diffractedlight) IL by the condenser lens 153 should be deviated from the incidentplane of the rod integrator 151.

Further, in this embodiment, the plane Q4 is assumed to be apredetermined plane (equivalent to the pupil plane of the optical systemor its conjugate plane); however the predetermined plane is not limitedhereto, and for example, it may be a plane between the rod integrator151 and the reticle R (or the reticle RA). In addition, when, forexample, any of the aperture stops 42 and 44 (or 42A and 42B) isemployed instead of the diffractive optical element 21 (or 22A etc.), orin combination thereof, its aperture stop may be arranged in thedownstream side (reticle side) of the rod integrator 151.

Additionally, in the above-mentioned first and fifth embodiments, in acase where both of the foregoing diffractive optical element andaperture stop are employed, thereby to set the distribution of amount oflight of the illumination IL on the pupil plane of the illuminationsystem, when the diffracted light to be generated from the diffractiveoptical element is distributed on the aperture stop as shown in FIG. 3or FIG. 7A, the utilization efficiency of the illumination light becomeshighest (the loss of the amount of light of the illumination light isminimized); however its diffracted light does not need to be accuratelydistributed as shown in FIG. 3 or FIG. 7A. That is, the utilizationefficiency of the illumination light is lowered; however the diffractiveoptical element different from the foregoing diffractive opticalelements (21 and 22) may be employed, thereby to distribute itsdiffracted light on a predetermined area including the area other thannine or five areas.

In addition, the aperture stop that is used in conjunction with theforegoing diffractive optical elements does not need always to have fiveor nine areas shown in FIG. 19 to FIG. 21, and the point is that it isenough to have the shading section or the light-reducing section forsetting the distribution of amount of light of the diffracted light(illumination light IL), which is generated from the diffractive opticalelement and is distributed on the pupil plane of the illumination systemor its conjugate plane, to the distribution of amount of light shown inFIG. 3, FIG. 6A, and FIG. 7A. For example, the diffractive opticalelement, which is employed for setting the distribution of amount oflight of FIG. 3 or FIG. 4, may be used in conjunction with the aperturestop for partially shadowing or light-reducing the center of the centerareas 29 or 33 of its distribution of amount of light, thereby to setthe distribution of amount of light of FIG. 6A or FIG. 7A, and nonecessity exists for forming the aperture, which corresponds to itsdistribution of amount of light (of five or nine areas in which theamount of light is enhanced) that should be set, on this aperture stop.

In addition, in the above-mentioned first and fifth embodiments, atleast one part of the optical system (4; 152 and 153) that is providedbetween the diffractive optical element to be arranged within theillumination system and the optical integrator (5; 151) is assumed to bea zoom lens (afocal system), thereby to make the size of the nine orfive areas, in which the illumination light IL on the pupil plane of theillumination system is distributed, variable. Further, at least one pairof the foregoing interval-variable prisms may be built in its opticalsystem (4; 152 and 153). At this time, so as to distribute theillumination light IL on the center area (28; 33), each of thevicinities of the apexes of one pair of the prisms is cut out, therebyto assume the part, through which the illumination light IL to bedistributed on the center area passes, to be an approximately verticalplane to the light axis BX of the illumination system.

Additionally, in the above-mentioned first and fifth embodiments, bymeans of the formation optical system (equivalent to the opticalmember), which is comprised of only a plurality of the diffractiveoptical elements that are arranged for replacement in the illuminationsystem, or the formation optical system having its plurality of thediffractive optical elements and the optical system, in which at leastone of the foregoing zoom lens and one pair of the prisms is built,combined, when the optical integrator is the fly eye lens 5, theintensity distribution of the illumination IL on its incident plane iscaused to change, and when the optical integrator is the inner-planereflection type integrator 151, the range of the incident angle of theillumination light IL that enters the its incident plane is changed,thereby allowing the distribution of amount of light (shape or size ofthe secondary light source) of the illumination light lL on the pupilplane of the illumination system, i.e. the illumination condition of thereticle to be changed arbitrarily. At this time, a plurality of thediffractive optical element to be hold in the revolver 24 are notlimited to only the foregoing diffractive optical elements 21 and 22,and may include at least one out of the four diffractive opticalelements to be used, for example, for each of the illuminating havingsmall σ, the annular illumination, the bipolar illumination, and thetetra-polar illumination. In addition, the foregoing aperture stop maybe combined with its formation optical system. At this time, forexample, one (including the foregoing diffractive optical element etc.except the aperture stop) out of the formation optical system may bearranged in the upstream side of the optical integrator (between thelight source 1 and the optical integrator), and its aperture stop may bearranged in the downstream side of the optical integrator.

In addition, in the above-mentioned first, and third, and fifthembodiments, the pitch in the X direction of three patterns 25A to 25Cshown in FIG. 2 is identical to that in the Y direction thereofrespectively, whereby as shown in FIG. 3, the straight lines 31A and31B, in which nine areas in which the illumination IL on the pupil planeof the illumination system is distributed are arranged, intersect eachother in the optical axis of the illumination system; however when thepitch in the X direction of three patterns 25A to 25C differs from thatin the Y direction thereof, the straight lines 31A and 31B do notintersect each other, that is, the distance in the X direction to theoptical axis differs from the distance in the Y direction hereto in fourmiddle areas 29A to 29D respectively, and yet the distance in the Xdirection to the optical axis differs from the distance in the Ydirection hereto in four most peripheral areas 30A to 30D respectively.Additionally, the number (kind) of the pattern to be formed on thereticle is not limited to three, and it may be two or four, and thearray directions of the pattern does not need always to coincide withthe X direction and the Y direction respectively.

In addition, in the above-mentioned first, third, and fifth embodiments,by means of a plurality of the foregoing interval-variable prisms, eachposition of the four or eight areas except the center area, in which thelight quantity on the pupil plane is enhanced, is made variable; howeverthe number of its neighboring area is not limited to four or eight, andfor example, two is acceptable.

Additionally, in the above-mentioned second, and fifth embodiments, in acase where both of the foregoing diffractive optical member and aperturestop are employed, thereby to set the distribution of amount of light ofthe illumination light IL on the pupil plane of the illumination system,when the diffracted light that is generated from the diffractive opticalsystem is distributed on the aperture stop as shown in FIG. 12 or FIG.16A, the utilization efficiency becomes highest (the loss of amount oflight of the illumination light is minimized); however its diffractedlight does not need to be accurately distributed as shown in FIG. 12 orFIG. 16A. That is, the diffractive optical element different from theforegoing diffractive optical elements 22A and 22B may be employed,thereby to distribute its diffracted light on a predetermined areaincluding the area other than three areas even though the utilizationefficiency becomes low.

In addition, the aperture stop, which is used in conjunction with theforegoing diffractive optical element, does not need always to have thethree apertures shown in FIG. 22, and the point is that it is enough tohave the shading section or the light-reducing section for setting thedistribution of amount of light of the diffracted light (theillumination light IL), which is generated from the diffractive opticalelement and is distributed on the pupil plane of the illumination systemor its conjugate plane, to, for example, the distribution of amount oflight shown in FIG. 12, FIG. 15 and FIG. 16A. For example, thediffractive optical element, which is employed for setting thedistribution of amount of light of FIG. 15A may be used in conjunctionwith the aperture stop for partially shading or light-reducing thecenter of the center area 54A of its distribution of amount of light,thereby to set the distribution of amount of light of FIG. 12, and nonecessity exists for forming the aperture corresponding to itsdistribution of amount of light which should be set (three areas inwhich amount of light is enhanced), on this aperture stop.

In addition, in the above-mentioned second and fifth embodiments, atleast one part of the optical system (4; 152 and 153) that is providedbetween the diffractive optical element to be arrange within theillumination system and the optical integrator (4; 152 and 153) may beassumed to be a zoon lens (afocal system), thereby make the size ofthree areas, in which the illumination light IL on the pupil plane ofthe illumination system is distributed, variable. Further, one pair ofthe foregoing interval-variable prisms may be built in its opticalsystem (4; 152 and 153).

Additionally, in the above-mentioned second and fifth embodiments, bymeans of the formation optical system (equivalent to the opticalmember), which is comprised of only a plurality of the diffractiveoptical elements that are arranged for replacement in the illuminationsystem, or the formation optical system, which has its plurality of thediffractive optical elements and the optical system, in which at leastone of the foregoing zoom lens and one pair of the prisms is built,combined, when the optical integrator is the fly eye lens 5, theintensity distribution of the illumination IL on its incident plane iscaused to change, and when the optical integrator is theinner-plane-reflection type integrator 151, the range of the incidentangle of the illumination light IL that enters its incident plane iscaused to change, thereby allowing the distribution of amount of light(shape or size of the secondary light source) of the illumination lightIL on the pupil plane of the illumination system, i.e. the illuminationcondition of the reticle to be changed arbitrarily. At this time, aplurality of the diffractive optical element to be hold in the revolver24 are not limited only to the foregoing diffractive optical elements 21and 22, and may include at least one out of the four diffractive opticalelements to be used for, for example, each of the small C illumination,the annular illumination, the bipolar illumination, and the tetra-polarillumination. In addition, its formation optical system and theforegoing aperture stop may be combined.

At this time, for example, one (including the foregoing diffractiveoptical element etc.) except the aperture stop out of the formationoptical system may be arranged in the upstream side of the opticalintegrator (between the light source 1 and the optical integrator), andits aperture stop may be arranged in the downstream side of the opticalintegrator.

In addition, in the above-mentioned second, fourth, and fifthembodiments, the pattern being an object of transfer, is the pattern ofthe one directional high density contact hole (one directional highdensity contact hole); however the pattern, being an object of transfer,can be regarded as a pattern that is substantially isolated in onedirection, and it is apparent that any pattern is acceptable so log asit is a pattern including the pattern to be periodically formed in thedirection intersecting it (for example, orthogonal hereto).

Further, in the above-mentioned second, fourth, and fifth embodimentsand its modified examples, three areas in which the amount of light isenhanced with the distribution of amount of light of the illuminationlight IL on the pupil plane of the illumination light system 12, whichis substantially conjugate with the pupil plane Q3 of the projectionoptical system PL, or its conjugate plane (or predetermined plane), areadapted to be arranged along a straight line, which is parallel to theperiodical direction of the foregoing one directional high densitypattern, on its predetermined plane, and passes through the optical axisof the illumination optical light system, however its three areas do notneed always to be arranged on the identical straight line. For example,out of the three areas, at least one of the remaining two areas exceptthe center area may be deviated from the above-mentioned straight linein the Y direction, and its two areas are caused to differ from eachother in the distances to the optical axis of the illumination systemwith regard to the Y direction light.

In addition, in the above-mentioned second, fourth, and fifthembodiments and its modified examples, the center area out of theforegoing three areas may be not only of circle shape but also ofannular shape or of square frame shape; however its shape (distributionof amount of light) is not restricted hereto. That is, with its centerarea, similarly to the annulus etc. the amount of light of the centerthereof may be set to be smaller than that of other part, and forexample, it may be comprised of a plurality of the areas (its shape isarbitrary), each of which is separated from the other. At this time, itsnumber or position of the plurality of the areas may be set so that thegravity center of amount of light of the center area approximatelycoincides with the optical axis of the illumination system, and forexample, the number is preferably the total 2n of n areas (n is anatural number) in which the center (gravity center) is out of theoptical axis and the distances to the optical axis are approximatelyidentical, and n areas which are symmetrically arranged to these n areaswith regard to the optical axis. In addition, the plurality of the areaseach of which is separated from the other in its center area may bearranged in a predetermined straight line that passes through theoptical axis of the illumination system 12 on the foregoingpredetermined plane, and, for example, may be arranged along theidentical straight line, and for example, maybe two areas to be arrangedalong the identical straight line. Further, with the plurality of theareas each of which is separated from the other in its center area, itsarray direction may be decided responding to the size of its center area(equivalent to the σ value), and it is preferable that its arraydirection is caused to approximately coincide with that (X direction) ofthe foregoing three areas, for example, when the size of the center areais relatively small, and conversely, it is preferable that its arraydirection is caused to be approximately orthogonal to that (X direction)of the foregoing three areas (that is, it is assumed to the Ydirection).

Moreover, in the above-mentioned second, fourth, and fifth embodimentsand its modified examples, while the positions of the remaining areasexcept the center area out of the foregoing three areas, i.e. thedistances to the optical axis of the illumination system with regard tothe direction (X direction) parallel to the periodical direction of theforegoing one directional high density pattern are kept approximatelyequal, they may be made variable responding to its pitch.

In addition, in each of the above-mentioned embodiments, the formationoptical system to be employed for altering the illumination condition ofthe reticle is adapted to include a plurality of the diffractive opticalelements; however instead of these diffractive optical elements, forexample, a plurality of the lens elements having different aberrationsmay be employed for replacement. Further, in case of employing the firstand second prisms 71 and 72 of which the periphery forms a cone,altering the interval of the prisms 71 and 72, i.e. the distance of eacharea, in which the intensity on the pupil plane of the illuminationsystem 12 is enhanced, to the optical axis BX allows the shape of eacharea to be changed responding to its alteration. Thereupon, when itschange quantity exceeds a predetermined allowable value, for example,the foregoing zoom lens, the foregoing cylindrical lens or the like maybe employed, thereby to suppress (lessen) a change in its shape.

In addition, the projection exposure apparatus of FIG. 1 may employ adouble integrator technique in which two optical integrators arearranged along the optical axis BX within the illumination system 12,and these two optical integrators differ from each other in its kind.Additionally, in the above-mentioned embodiments, the distribution ofamount of light of the illumination light on the pupil plane of theillumination system is enhanced in a plurality of the areas; however,for example, when the amount of light is reduced gradually, theso-called area in which the amount of light is enhanced points to thearea in which the amount of light becomes equal to or more than apredetermined value.

Additionally, in each of the above-mentioned embodiments, in a case ofemploying vacuum ultra violent light having a frequency of, for example,less than 180 nm or something like it as the illumination IL, theoptical material of the refractive member such as the substrate of thediffractive optical elements 21, 22, 22A, and 22B, the glass substratecomposing the reticles R and RA, and the lens composing the projectionoptical system PL is preferably formed of the material selected from agroup of fluoride crystal such as quartzite (CaF₂), magnesium fluoride,and lithium fluoride, quartz glass having fluorine and hydrogen doped,quartz glass of which the structure determining temperature is 1200 K orless, and yet of which the hydroxyl group concentration is 1000 ppm ormore (for example, disclosed in Japanese Patent No. 2770224 publicationby filed this applicant), quartz glass of which the structuredetermining temperature is 1200 K or less, and yet of which the hydrogenmolecule concentration is 1×10¹⁷ molecules/cm³ or more, quartz glass ofwhich the structure determining temperature is 1200 K or less, and yetof which the base concentration is 500 ppm or less, and quartz glass ofwhich the structure determining temperature is 1200 K or less, of whichthe hydrogen molecule concentration is 1×10¹⁷ molecules/cm³ or more andyet of which the chlorine concentration is 50 ppm or less (For example,disclosed in Japanese Patent No. 2936138 publication by filed thisapplicant (corresponding to U.S. Pat. No. 5,908,482)). On the otherhand, in case of employing the ArF excimer laser beam, the KrF excimerlaser beam or the like, it is possible to employ the synthesized quartsin addition to each of the above-mentioned substances as its opticalmaterial.

Next, one example of the process for fabricating the semiconductordevice using the projection exposure apparatus of the above-mentionedembodiments will be explained with a reference to FIG. 24.

FIG. 24 shows an example of the process of fabricating the semiconductordevice, and in FIG. 24, at first, a wafer W is fabricated from a siliconsemiconductor etc. Thereafter, a photo resist is coated on the wafer W(step S10), and in a next step, the reticle R1 is loaded onto thereticle stage of the projection exposure apparatus of theabove-mentioned embodiments (FIG. 1A or FIG. 18) to transfer (expose)the pattern (donated by a code A) of the reticle R1 (for example, thereticle R of FIG. 2) to the entire shot areas SE on the wafer WE withthe scan exposure system. Additionally, the wafer W is for example, awafer having a diameter of 300 mm (12-inch wafer), the shot area SE ofwhich the width is 25 mm in the non-scan direction and 33 mm in the scandirection respectively, is of rectangular area. Next, in a step S14, byperforming the developing, the etching, and the ion implantation, apredetermined pattern is formed in each shot area of the wafer W.

Next, in a step S16, the photo resist is coated on the wafer W (stepS10), and thereafter, in a next step S18, the reticle R2 (for example,the reticle RA of FIG. 11A is loaded onto the reticle stage of theprojection exposure apparatus of the above-mentioned embodiments (FIG.1A or FIG. 18) to transfer (expose) the pattern (donated by a code B) ofthe reticle R2 (for example, the reticle R of FIG. 2) to the entire shotareas SE on the wafer WE with the scan exposure system. In additionhereto, in a step S20, by performing the developing, the etching, andthe ion implantation, a predetermined pattern is formed in each shotarea of the wafer W.

The exposure step to the pattern formation step described above (stepS16 to step S20) are repeated by the number of times necessary forfabricating the desired semiconductor device. In addition hereto,through the dicing step of cutting each chip CP off the wafer W one byone (step S22), the bonding step, the packaging step (step S24) etc. thesemiconductor device SP is fabricated as a product.

In addition, the illumination system to be composed of a plurality oflens and the projection optical system are built in the main frame ofthe exposure apparatus to make an optical adjustment, and the reticlestage and the wafer stage to be composed of a number of machine partsare mounted on the main frame of the exposure apparatus to connect thewiring cables and the pipes, and to further make a comprehensiveadjustment (electric adjustment, operational confirmation, etc.),thereby enabling the projection exposure apparatus of theabove-mentioned embodiments to be manufactured. Additionally, theprojection exposure apparatus is desirably manufactured in a clean roomin which the temperature and the cleanliness are controlled.

In addition, needless to say, the present invention can apply not onlyto the case of making an exposure with scan exposure type of theprojection exposure apparatus, but also to the case of making anexposure with the batch exposure type of the projection exposureapparatus such as the stepper. The scale factor of the projectionoptical system in these cases may be a one-to-one factor, and may be anenlarged scale factor. Further, the present invention can apply, forexample, to the case of making an exposure with the liquid-penetrationtype of the projection exposure apparatus disclosed in internationalPublication Number (WO) 99/49504 etc. The liquid-penetration type of theprojection exposure apparatus may be of the scan exposure techniqueemploying the reflective/refractive type of the projection opticalsystem, or may be of the static exposure technique employing theprojection optical system of which the projection scale factor is ⅛. Inthe latter liquid-penetration type of the projection exposure apparatus,so as to form a large pattern on the substrate, the step and stitchtechnique explained in the above-mentioned embodiment is preferablyemployed.

Additionally, the application of the liquid-penetration type of theprojection exposure apparatus of the above-mentioned embodiment is notlimited to that of the exposure apparatus for fabricating thesemiconductor element, and for example, it can be widely applied for theexposure apparatus for the display apparatus such as the liquid displayelement or the plasma display, which is formed on the angular glassplate, or the exposure apparatus for fabricating the various devicessuch as the imaging element (CCD etc.), the micro-machine, the thinlycoated magnetic head, and the DNA chip. Further, the present inventioncan apply to the exposure step (exposure apparatus) in fabricating thereticle having the reticle pattern of the various devices using thephotolithography step.

The aforementioned disclosures of all the United States Patents etc. areincorporated herein by reference, as far as the national laws of thedesignated states designated in the present international application orthe elected states elected in the present international applicationpermit.

The present invention is not limited to the above-mentioned embodiments,and the invention may, as a matter of course, be embodied in variousforms without departing from the gist of the present invention.Furthermore, the entire disclosure of Japanese Patent Applications2003-105920 filed on Apr. 19, 2003, 2003-299628 filed on Aug. 25, 2003,2003-307806 filed on Aug. 29, 2003, 2003-329194 filed on Sep. 19, 2003,2003-329309 filed on Sep. 22, 2003 including description, claims,drawings and abstract are incorporated herein by reference in itsentirety.

INDUSTRIAL APPLICABILITY

In addition, in accordance with the method of fabricating the device,the device including the various patterns can be manufactured with ahigh precision and yet with a high throughput.

In addition, in the method of fabricating the device of the presentinvention, when the distribution of amount of light on a predeterminedplane with regard to the illumination system is set so that the amountof light is enlarged in a predetermined three areas, the deviceincluding the one-direction mass pattern can be fabricated at a highprecision.

1. An exposure method for illuminating a pattern with an illuminationsystem to expose a substrate through a projection system, wherein thepattern is illuminated with illumination light with a light amountdistribution in which an amount of light is larger in a pair of firstareas and a pair of second areas than in an area other than the firstand second areas, the pair of the first areas being arranged outside anoptical axis on a pupil plane of the illumination system, the pair ofthe second areas being arranged on the same straight line as the pair ofthe first areas are arranged on and the pair of the second areas beingarranged outside the pair of the first areas.
 2. The exposure methodaccording to claim 1, wherein the pair of the first areas areapproximately at the same distance from the optical axis in a directionparallel to the straight line, and the pair of the second areas areapproximately at the same distance from the optical axis in thedirection parallel to the straight line.
 3. The exposure methodaccording to claim 2, wherein the straight line passes through anoptical axis of the illumination system on the pupil plane.
 4. Theexposure method according to claim 3, wherein the pair of the secondareas respectively have longitudinal directions which are substantiallycoincident with a direction orthogonal to the straight line.
 5. Theexposure method according to claim 2, wherein a size of the first areaand a size of the second area are different.
 6. The exposure methodaccording to claim 5, wherein the size of the second area is larger thanthe size of the first area.
 7. The exposure method according to claim 2,wherein an amount of light in the first area and an amount of light inthe second area are different.
 8. The exposure method according to claim7, wherein the amount of light in the second area is greater than theamount of light in the first area.
 9. The exposure method according toclaim 1, wherein the illumination light distributed in the second areasis substantially linearly polarized light.
 10. The exposure methodaccording to claim 9, wherein a direction of the linearly polarizedlight is substantially coincident with a direction orthogonal to thestraight line.
 11. The exposure method according to claim 1, wherein theillumination light in the first areas and the illumination light in thesecond areas have different polarization states.
 12. The exposure methodaccording to claim 11, wherein the illumination light distributed in thefirst areas and the illumination light distributed in the second areasare linearly polarized and a polarization direction of the illuminationlight distributed in the first areas is substantially orthogonal to apolarization direction of the illumination light distributed in thesecond areas.
 13. A device manufacturing method, comprising: exposing asubstrate by the exposure method as recited in claim 1; developing theexposed substrate; and processing the developed substrate.
 14. Anexposure method for illuminating a pattern with an illumination systemto expose a substrate through a projection system, wherein the patternis illuminated with illumination light with a light amount distributionin which an amount of light is larger in four areas than in an areaother than the four areas, the four areas being arranged on a straightline passing through an optical axis on a pupil plane of theillumination system.
 15. The exposure method according to claim 14,wherein the illumination light distributed in areas at both ends of thefour areas is substantially linearly polarized.
 16. An exposure methodaccording to claim 14, wherein areas at both ends of the four areasrespectively have directions orthogonal to the straight line on thepupil plane as longitudinal directions.
 17. The device manufacturingmethod, comprising: exposing a substrate by the exposure method asrecited in claim 14; developing the exposed substrate; and processingthe developed substrate.
 18. An exposure apparatus, comprising: anillumination system which illuminates a pattern; and a projection systemwhich projects the pattern onto a substrate, wherein the exposureapparatus comprises: a formation optical system which can change a lightamount distribution of illumination light on a pupil plane of theillumination system and which can generate a light amount distributionin which an amount of light is larger in a pair of first areas and in apair of second areas than in an area other than the pair of the firstareas and the pair of the second areas, the pair of the first areasbeing arranged outside an optical axis on the pupil plane and the pairof the second areas being arranged on the same straight line as the pairof the first areas are arranged on and the pair of the second areasbeing arranged outside the pair of the first areas.
 19. The exposureapparatus according to claim 18, wherein the pair of the first areas areapproximately at the same distance from the optical axis in a directionparallel to the straight line, and the pair of the second areas areapproximately at the same distance from the optical axis in thedirection parallel to the straight line.
 20. The exposure apparatusaccording to claim 19, wherein the straight line passes through theoptical axis of the illumination system on the pupil plane.
 21. Theexposure apparatus according to claim 20, wherein the pair of the secondareas respectively have longitudinal directions which are substantiallycoincident with a direction orthogonal to the straight line.
 22. Theexposure apparatus according to claim 19, wherein a size of the firstarea and a size of the second area are different.
 23. The exposureapparatus according to claim 22, wherein the size of the second area islarger than the size of the first area.
 24. The exposure apparatusaccording to claim 19, wherein an amount of light in the first area andan amount of light in the second area are different.
 25. The exposureapparatus according to claim 24, wherein the amount of light in thesecond area is greater than the amount of light in the first area. 26.The exposure apparatus according to claim 18, wherein the illuminationlight distributed in the second areas is substantially linearlypolarized light.
 27. The exposure apparatus according to claim 26,wherein a direction of the linearly polarized light is substantiallycoincident with a direction orthogonal to the straight line.
 28. Theexposure apparatus according to claim 18, wherein the illumination lightin the first areas and the illumination light in the second areas havedifferent polarization states.
 29. The exposure apparatus according toclaim 28, wherein the illumination light distributed in the first areasand the illumination light distributed in the second areas are linearlypolarized and a polarization direction of the illumination lightdistributed in the first areas is substantially orthogonal to apolarization direction of the illumination light distributed in thesecond areas.
 30. A device manufacturing method, comprising: exposing asubstrate with the exposure apparatus as recited in claim 18; developingthe exposed substrate; and processing the developed substrate.
 31. Anexposure apparatus, comprising: an illumination system which illuminatesa pattern; and a projection system which projects the pattern onto asubstrate, wherein the exposure apparatus comprises: a formation opticalsystem which can change a light amount distribution of illuminationlight on a pupil plane of the illumination system and which can generatea light amount distribution in which an amount of light is larger infour areas than in an area other than the four areas, the four areasbeing arranged on a straight line passing through an optical axis on thepupil plane.
 32. The exposure apparatus according to claim 31, whereinthe illumination light distributed in areas at both ends of the fourareas is substantially linearly polarized.
 33. The exposure apparatusaccording to claim 31, wherein areas at both ends of the four areasrespectively have directions orthogonal to the straight line on thepupil plane as longitudinal directions.
 34. A device manufacturingmethod, comprising: exposing a substrate with the exposure apparatus asrecited in claim 31; developing the exposed substrate; and processingthe developed substrate.